Re: Who dies?
I'm actually hoping that it's Nick Fury. He's the man who brought The Avengers together. He was the one who didn't allow for a nuclear strike on New York. Nick Fury dying, being replaced with Maria Hill and having a new director who's far less sympathetic to The Avengers who'll lead a darker SHIELD and might butt heads with the rest of the cast is incredibly interesting to me.
I wouldn't kill off more than one character for this since Avengers 3 with Thanos is the opportunity to murder most of the cast. If I had to choose anyone else, it would be Hawkeye. He'd have so much tension with Cap over Black Widow and then having himself die a noble sacrifice for Cap would be all worthwhile. Of the main six, I doubt that Hawkeye will ever get his own film so having him go out in a blaze of glory would be the right way to handle him.