I suspect everyone here is putting far more thought into this than the writers did with the last Star Trek film, and probably more than they will put into the next Trek film. Seriously, did anyone think when we heard Trek 09 was going to be a reboot that the plot would consist of 'Romulan mining ship travels back in time, kills Kirk's dad, gets captured for the next twenty or so years and then escapes and uses magical plot goo to destroy Vulcan'?
Because ... that wasn't my first thought for what they'd go with. If I had to make a prediction about the next Trek film it would be that none of us will be able to remotely predict the plot of it.
That was a completely blank slate.
However you didn't even have to predict "CREW OF THE ENTERPRISE SAVES THE DAY!".
They have to do that again, or at least build towards it in a third movie.
There is a set of logical assumptions and rules that exist now that one would hope that the writers would follow up.
1: A Romulan ship wiped out an entire Klingon fleet and the Klingons are gonna be pissed.
2: The Romulans have no clue what has been going on, or that the Klingons are pissed at them.
3: Spock is in the timeline and has no qualms about helping out his old friends and crew or the Federation.
4: The entire time frame of events have been completely altered and nothing that happened in TOS, TNG, DS9 or VOY can ever possibly happen.
Based on #1: The Klingons may attack the Romulan empire.
Based on #2: The Romulans will probably not be at all prepared and the reason Nero went back in time, to save the Romulans, may end up being a moot point.
Based on #3: Spock could give his genetic cousins a heads up and will probably use reunification as a way to prop up the Vulcan people and keep them from the brink of extinction. This means information and technology exchanges and advancements. Not just for the Vulcans, but the Federation as well to protect the remaining Vulcans.
Based on #4: This is the big one... No Kitamer, (sp?) no Borg, no Dominion, no Space Seed, no Trouble with Tribbles, no anything that has ever happened in the original timeline. Literally nothing that involved TOS crew, with the exception of anything that was not stumbled on, discovered, or initiated by them, such as the Whale Probe from STIV, V-Ger from STI, etc., and these are all things that Spock will most certainly brief Starfleet on as he would know that there is no way to predict where the crew of the Enterprise will be now that it's 5 year mission, has started much sooner.
Here's an interesting thought...
I think it is obvious that the timeline was already altered when Spock and the Narada encountered Kirk Sr's ship. This could be accounted for by TOS crew never going back in time to snatch the whales and taking that doctor back with them. Don't think that is feasible? Look what happened in The City on the Edge of Forever when one woman was saved.
There are a ton more that I could spend a week talking about, but the thing is, everything is a blank slate and everything can be different now. There are no rules of continuity to follow, which is good as it will allow new fans to watch without being bogged down in ST lore and if they do decide to make a little tip of the hat to original events it will be a fun nod to the die hard fans.
Kirk: "Why do we have to have this old radio hooked up Spock?"
Spock: "My counterpart said it would be a good idea based on his experience."
McCoy: "Is that why we had to go get those damned whales?"