It's no offense to you as we are all allowed to think what we want and I am not specifically calling you out--but I still think this is one of the worst ideas I've ever heard.
This would mean either:
A) Hulk is barely in it except for to smash crap. (Yay.

)
or
B) We get a walking talking Hulk running around completely controlled by Banner and completely killing any little conflict for his character. That's it. Hulk/Banner is essentially God at this point. He can control it, he can't be stopped, bad guys lose. (Yippee.)
and most definitely
C) You are asking us to stare at just a computer generated character for the entire movie. As if Hulk in both '03 and '08 didn't have consistency issues in the first place. (As did Dr. Manhattan in Watchmen.)
No... just no. Recast the guy if you can't get him, but to throw out the character, the heart and soul of the Hulk/Banner relationship by completely eliminating Banner from the mix is just a terrible idea to me.
This movie needs to be a story about all of the Avengers and their interactions with each other... not "Lolz, let's throw a bunch of heroes in there just for the fun of it!" Hulk needs a reason to be there, he needs a conflict (or to cause one), he needs a purpose. As someone else said, don't let this become an X-men with one or two stars and the others just being extended cameos.