I guess part of the problem is any of the EU crap I've read with the Sith in it present them as pretty much evil-evil. There's nothing seductive, alluring, or persuasive about them. It's all "rah-rah, kill your friends, kill your family, lulz about the dark side and get sith-faced." They're all pretty much locked into a teenager's concept of evil badassery.
The EU is a huge, monstrous thing, with many semi-contradictory sources. I stopped following it closely years ago, so this whole "everyone is a backstabbing murderer" thing is something I just picked up in this thread from you guys.
It sucks when writers get specific like this, without actually thinking through their details. I liked the portrayal in other sources which were more vague, yet more sensible on the matter. The "Sith" title almost seemed like semantics, because Palpatine and other Sith seemd to have no problems taking on lesser trainees who may not have rated as full Sith Lords. The RPG materials described High Inquisitor Tremayne, there were several Force-wielding Emperor's Hands, the Jedi Knight
computer games had Jerec and Desann, and the Clone Wars
cartoon had Asajj Ventress. The impression that I got was that "Sith Lord" is the equivalent of "Jedi Master," and that the Sith could have lesser apprentices around. Even the Original Trilogy had Palpatine and Vader trying to convert Luke in TESB, and I doubt that convincing Luke to murder Vader was always part of that plan before ROTJ.
When Yoda says there are always two Sith, "no more, no less," it should be noted that he's not in a position to speak authoritatively. Now on one hand, when it comes to fiction, lines are an expressions of authorial intent. But in-universe, Yoda is literally going off of information more than a thousand years out-of-date, which is when the Sith were thought to have gone extinct. The idea of every Sith following Darth Bane's rule is kind of dumb, when the Sith are an order of one master. If a Sith Master doesn't like the rule, he can change it just like that.
And the prequel movies themselves even imply a rather loose interpretation of the Rule of Two. Palpatine must have been courting Dooku around the same time that Maul was still alive, which was "ten years" before AOTC. General Grievous was "trained in the Jedi arts" by Dooku, with full knowledge of Palpatine. The EU has come up with its own non-Force related origin for Grievous, but apparently Lucas's intention was that he was a disgruntled failed Jedi
who turned to cybernetics to make up for the power that he lacked. So in Lucas's mind, Grievous was pretty much another low-level Sith trainee.
I like what was implied in the movies, or shown in various other EU sources, so much more than the strict portrayal of the "Rule of Two" in several of the books.
"They're not triangular, but they are more or less blade-shaped"
- Thrawn McEwok on the shape of Bakura
"Lovely. It's known as impugning character regarding statement of professional qualifications' in the legal world"
- Karen Traviss, crying libel because I said that no soldier she interviewed would claim that he can take on billion-to-one odds
"I've already laid out rules for this thread that we're not going to make these evidential demands"
- Dark Moose on supporting your claims