Re: Who dies?
If you saw Thor 2's mid credits scene there's zero doubt where the franchise is headed. Robert Downey Jr has been causing all sorts of problems for Marvel, Iron Man 4 is unlikely, and Iron Man 3 completed his character arc nicely. Avengers Age of Ultron will put Stark right back where he started, creating a weapon for the greater good that destroys and hurts more than it helps. Whedon knows killing beloved characters raises the stakes, he called Avengers 2 the "Empire Strikes Back" of the franchise, and let's face it- Tony is definitely our Han Solo.
It's good storytelling to have Iron Man die in this film to be honest. He made a point of saying he was given a second chance at life in the cave, over and over. By this point he's overcome all his short comings, including the reliance on his armor. When the script was written Marvel was unsure Downey would reprise his role. It just makes sense that Stark will have to die before the credits role.
Now given the Infinity Gauntlet is coming into play most likely he will be resurrected for the big fight with Thanos inadvertently. Afterall the "return" of such a popular character would be a HUGE box office draw so financially it would make sense as well. I could really go on about why it makes so much sense that Iron Man is going to go but I know no one wants to read all that haha.