I trust Whedon to make a good Avengers movie yeah, but the balance in the first movie was way in Stark's/Iron Man's favor, so balance is still something I'm weary about.
I would bet money that this is inaccurate. Tony got a character beat with Pepper at the start and got to make the "Avengers" speech to Loki, beyond that I have a hard time believing he had any more screen time than the rest of them.
Is Renner still sticking around? I thought he was getting replaced?
There were threats on both sides during negotiations, but everybody from The Avengers is returning. Most signed through Avengers 3.