I've been told RL armour doesn't really stand up past a few shots either, so I'm not sure why this would be seen as an issue. All it might do is protect you from one shot, but if so, that's fine - all it takes is one shot to kill someone.
The bigger issue might be that a shield would bounce the blaster bolt off you and ricochet into someone else or something else. Or armour is cheaper than fielding personal shields.
forgot about this one.. I meant to address it.. sorry for the tl;dr nature.. but its kinda complicated
(the explanation isnt wholly directed at you either Stofsk, I just didnt feel like making separate posts to cover the whole 'armor vs shield' bit lol)
RL body armor as I understand it isn't "perfect" - that is it doesnt guarantee lack of injury, it is meant to minimize the lethality as much as possible (which could mean alive with bruises or broken bones due to blunt force trauma, or meaning you're alive with the wind knocked out of you.) I still believe it is possible (although a rmote chance) for even a fully intact vest to be penetrated, and certain kinds of weapons (even with plates covreing vitals) could still do serious injury even if they don't penetrate. Penetration/resistance to penetration in bullet/vest impacts also depends on alot of factors (angle, how close to earlier shots other shots land - from what I recall if two bullets landed on nearly the same point penetration could/would occur even in modern body armor), enviromental conditions, bullet type (vests are rated against different kinds of bullets and velocities both, which is partly the reason of ambiguity) Someone in the military (or Sea Skimmer) probably could clarify this betteR (and correct me on any mistakes I made above, I may have made some lol)
When it comes to storm trooper/clone trooper armor, things can get alot more complicated. For example: You have to worry about multiple kinds of attacks now, both of a projectile and energy/beam weapon varety (not just bullets.). This can even subdivide (energy weapons could be lasers or particle beams or heat rays or something omre exotic, and the same can be said for projectile weapons.) and there are few reliable ways of easily, effectively protecting against all kinds of attacks. (EX: lasers can be continous heat rays, cutting beams, and/or simulate explosive/mechanical damage effects, may be a single pulse or series of pulses, etc and may exhibit variable penetration depending on frequency. Particle beams can be harder to stop than lasers - eg more penetrative - and may also do thermal and/or mechanical damage and so on.) It is possible some of this will overlap to an extent (EG mechanical and thermal damage for both lasers and particle beams could be somewhat combined, but the penetrative qualities of particle beams is still a problem.)
Since mass and volume are going to be considerable constraints on what you can do, this means you have to compromise protection in some way. Or do something exotic like adopt power armor and really really thick plates of high tech armor. Or spend money and use high tech materials (They exist, but assuming they aren't too heavy for personal use, are likely to be quite expensive, which could cause problems with deployment.)
More likely, designers will try to customize. You can for example optimize against certain kinds of attacks (stormtrooper armor being highly resistant to kinetic impacts, at least in some cases, or clone commando Katarn armor being both more sophisticated and optimized against energy attacks to the point that it can stop light laser cannon hits but not grenades easily.) Or you may sacrifice protection for lower weight and greater mobility/comfort (scout armor) or possibly whatever other reasons (extra equipment like cold weather gear or desert situations, although what compromises those entail in ST armor we don't know). You may even choose to increase weight for varying reasons (Rad trooper and other hostile enviroment troopers, as well as the fact Clone armor is heavier than stormterooper armor.) But optimizing means that you'll be weaker against other kinds of attacks of course (which may very well explain cases when spears penetrate armor, and such.) And increasing the weight, while offsetting that, can have nasty consequences for your troopers if they have to engage in long term duty over prolonged periods (a problem faced in Iraq by troops, for example, cuz their gear is so damn heavy.) Optimizing is more of a "specialist" option - its likely to be used when/if you know or are sure the enemy may or may not have certain kinds of weapons (EG you know your enemies dont' have high energy blaster rifles you might optimize for projectile weapons, which seems to be standard stormtrooper configuration. The Empire seemed to compensate here by trying to greatly restrict blaster technology to reduce how available more lethal kinds are.)
If you don't know for sure or have little intel, then your armor is goign to have to be more "generalized" - cover as broad an area of weaponry as possible to maximize protection against all possible threats. The compromise here is that you aren't able to defend as effectively against a certain kind of attack.
There are certain caveats above, though. For one thing, unless you have some sort of easy access to rapid, automated fabrication from existing mateirals (which is possible) there is bound to be a limit on the variety of armor plate one can stock (pre made, pre optimized, in other words.) While in theroy Star wars could "custom fabricate" any sort of defense plating thy wanted for their body armor onboard ship (or at least should be capable given edemonstrated capabilities) this is not neccesarily something the Empire (or others) automatically use, at least on ship (ISDS dont seem to recycle, at least.) Which means that the armor plate has to be fabricated elsewhere, and cannot be easily "customized" on the fly. Since you cannot carry an infinite number of plates, and you have to balance diversity vs stock quantity onboard, certain concessions have to be made and optimization of armor may be limited (or nonexistent) The other point is that alot of the "kinds" of protection that may be required can also depend on "current" technology. While SW has a largely stagnant tech base in the sense nothing is innovated, what they do have does get refined and upgraded sometimes (EG the Death Stars). Along with that is that there are technological "trends" that can shift - some weapons may fall out of use (projectile weapons, lasers) in favor of others (particle beams, exotic, etc.) so protection may choose to sacrifice certain "outdated" forms of defense to optimize more currently known and liklier ones.
It gets even better. Let's say that the above doesn't apply and you only have to worry about one kind of blaster. Doesnt matter much if its laser or particle or exotic or whatever. Let's go by what we know from the movies alone.
We know blasters from the movies can range from having extensive thermal effects, to explosive effects (burning/boiling/cremating people on the thermal end, to exploding big holes from the wall on the 'simulating explosive effects" end.) Any armor you see, in theory, has to be able to block against both sorts of attacks. Explosive effects are going to be messier and more efficient and more likely to be rapidly fatal. So armor should do its utmost, first and foremost, to mitigate those effects. Simulating an explosive via energy weapon involves three main (to simplify) critera - sufficient energy to vaporize a given quantity of material (which can include body and armor via rapid heating) the ability to deliver that energy very rapidly (microseconds or nanoseconds ideally), and concentrating that energy on a very small area (centimeters to millimeters or less. He smaller the area the less energy you might require and the higher the pressure that probably will build.) It's a bit more complicated than that, but those three qualities will suffice to illustrate my point.
Now, armor can affect any of those qualities. One way is to rapidly spread the energy over a wider surface area, making it harder for the shot to penetrate or simulate the explosive. It might (handwave) some way to play around with the time factor at the same time (the longer it takes to simulate the explosive, the less force will result. Think of the difference between dynamite and gunpowder.) Armor may even try to ablate away to prevent this happening. Lots of options and any may apply (the vapor or sparks we sometimes see could be ablation in some cases, for example.)
If there is "explosive" effects of any kind, you'll want to again try to cushion and spread the effects evenly (similar to what real life body armor does with bullets) which may still result in injuries over a larger scale
This could be merely incapacitating instead of fatal, or the person may survive it. Again there could be some overlap here between this and other kinds of protection (EG high explosives).
Canonically, we never see blaster bolts that actually blow large, gory holes in people. They may be badly burnt or cooked (EG Greedo) or have nasty holes burned through them (Jedi, occasional stormtrooper), but they are still more or less intact. This leads me to think body armor is primarily optimized against the mechanical/explosive effects of blasters first and foremost, and is VERY effective at stopping that. (which I think would also make some sense from the projectile weapon and explosives resistance angle too.)
That leaves thermal. ST armor and clone trooper armor supposedly allows bodies to go through shield interfaces without injury, as well as adverse thermal conditions like mustafar, so we know that against large area, non localized thermal effects body armor is somewhat effective. Less localized can be another story. And this is where things get a bit messy.
As I said before, we know from the movies that armor seems mainly effective at stopping explosive blaster damage from occuring. But with a sufficiently energetic blaster bolt, it is still possible for damage to occur. In addition to the force/shock effects I alluded to above possibly, there is also considerable thermal danger. After all, waht I described above is that SW armor probably tries to spread the energy over a wider area. But that energy does not disappear, and it has to go somewhere. We know ST armor has heat sinks (as per the ICSes) but they don't seem to radiate very effecitvely (at least ST don't glow bright, and they don't cook any nearby visible flesh), so its likely that the body armor is meant to siphon off the absorbed thermal energy into the belt sinks. We dont know how quickly it can do that, but it does present some interesting thoughts. If the body armor does not rid itself of energy quickly enough, it could be heated to lethal levels by subsequent shots. And since it will try to spread the energy over a wider area, it will be heating a large area of the body... which is very much like what we see with Greedo, with Grievous, etc.
Thermal damage could manifest in various ways depending on the armor or strength of a shot. It doesn't take alot of energy to actually burn someone fatally if you do it right (flash burns int he 2nd/3rd degree can come from as little as 50 J applied per cubic centimeter of body, for example) but even that can come up to tens or hundreds of kilojoules easily (but more gradual burning could be more energetic, as with scald burns which often requires water at or above 120F, nevermind stuff like superheated steam.) Fatal temperature changes (EG heatstroke) could also be a danger (the intenral conditions of a "heated" piece of armor could overwhelm enviromental controls, for example and the body cooks alive in the armor) Eithre would not neccesarily be immediately fatal, but painful and certainly incapacitating. A sufficiently energetic shot might simply brute force burn its way through and cook internal organs, I suppose. Lightsabers appear to do that (TPM) for example.
This also means a sufficiently energetic "heavY" shot could also end up inflicting thermal damage through the armor. There's not alot of ways to get around this either since as i said energy doesn't disappear and venting it into the surroundings may either be impossible (radiators don't minimize that small, and radiating armor has other considerations like cost or complexity or civilian concerns) - penetration has to be factored in here as well. By the time the armor sufficiently diffuses the shot it may have penetrated partly, mostly or completely through the armor, even if it "saves" the person.
Also, as horrifying as it may sound, extenstive thermal effects COULD have desirable side effects, to some extent. If a blaster bolt did make a messy explosive wound that bled, it may be inefficient enough to make the wound smaller, but also cauterize the wound, which would save the person from bleeding to death. Of course a big enough wound could reuslt in nasty, large scale burning of the body which is lethal in its own way, but its better than nothing. In truth the extreme thermal effects would probably be the blaster analogue to the "blunt force trauma" of a bullet impact on modern body armor (eg its something that can't just disappear, you can only manipulate it so that it hopefully is less lethal).
There's also the possibility armor is designed to protect agains stun effects, since stun is never used on armored troops onscreen. It may even be that a damage component of "lethal" blaster bolts is a more powerful (and possibly more lethal) stun effect, as I have alluded to in the past, which has to be dealt with, which is going to provide further dilution of protection as I noted above.
Personal shielding would probably simplify the blaster angle at least s far as thermal effects go, but as I noted shields have their own drawbacks . In reality any "practical" personal shield probably won't do more than shield against thermal damage that hits the target, and largely only provide an effective "Heat sink" - radiation probably is still impossible (or unsafe) at that scale, and thus limit the shield to whatever capacity the heat sink provides. And cost will almost certainly limit the heat sink. The other problems (Optimization -while armor can be optimized too, I suspect the problem is far worse for shields givne the ray/particle shielding duality among other things - enviromental considerations, power usage, compelxity, and detectability.) still apply too.