Re: Who would you let Joss Whedon kill in Avengers 2?
Dr. Selvig, Maria Hill and possibly Pepper Potts and/or Jane Foster. Treat them like Coulson in the Avengers. Use them as en emotional driving force for the movie. You have to up the ante. You killed a fan favorite in the first one, can't (or shouldn't) kill a primary Avenger and you could only kill Fury if you'll put Stark in charge.
Just my opinion. Keep in dark, keep the emotions high... maybe even kill Hawkeye.... MAYBE.