The Avengers 2 and 3 will not centre around a Planet Hulk storyline.
That is the declaration from director Joss Whedon, when asked if future Avengers movies would make use of the Planet and World War Hulk comic series’, as has been speculated recently.
“Well I’m really not supposed to comment, but no, that’s nonsense.”
The denial can be seen in a video at the link below, and seems pretty definitive. It seems the recent report of Marvel not wanting to do a solo Hulk project without Bruce Banner getting sufficient screen time is accurate, and given the response to Mark Ruffalo’s performance in The Avengers, who can blame them.