Ancient aliens created space rings to kill all life because of an unstoppable species that fed on all life. Turns out it didn't kill the species so Master Chief has to shoot them and stuff. Also a ton of mystical BS. At least that's what I got from the first two games, haven't played any since.
I'm not furious over them like a lot are, I'm just not that interested.
Sam as Cap seems cool, I just haven't liked Remender's run on Cap.
No issues with Thor other than Marvel has been so misleading as to if she's a whole new character or she is replacing the original Thor. The way they're handling it just feels like an attention grab to make themselves appear more progressive to non-comic media by making one of it's top characters have a female version. Why not a new character or give a boost to an already existing one?
As for Iron Man, Extremis was one of the best stories to come to his character in years and Marvel really doesn't want to let the idea of the extremis serum's power go . Over use of it is kind of going to make the original story less important as the tech was supposed to be too powerful that no one could be trusted with it's capabilities. Yet Marvel just can't let go of it!