A Planet Hulk movie is currently all the rage amongst the online chatter.
The comic book storyline saw Marvel heroes trick the Hulk into space in a plan to maroon the Green Goliath on a planet where he would no longer be bothered and would no longer bother anyone else. The only problem is that instead of going to the planet, the Hulk goes through a wormhole and ends up a slave on the planet Sakaar.
Now Joss Whedon weighs in on a potential Planet Hulk movie with IGN offering it would be really expensive and at the same time says a Hulk movie should be more grounded and center around Banner. The Planet Hulk comic storyline featured virtually none of Banner as the Planet Sakaar was considered too dangerous for the puny Banner to survive so they remained in Hulk form.
It absolutely could be put onscreen. I don’t know if it should. I think part of what makes the Hulk great is the world around him and the Banner of it. And it would be mad expensive as well. I think if they were going to do a Hulk movie, they’d want to keep it more grounded.
Regarding the comment of Planet Hulk not featuring Banner, which Feige has also mentioned, obviously the movie could just be a different adaptation with more Banner elements added to the film.
Whedon also talks about the Hulk in both of his Avengers movies and offers his take on two different versions of the Hulk. Warning: There is a slight spoiler.
"I always think that there are basically two Hulks. There’s horror movie Hulk and superhero movie Hulk. In the first film we got a taste of both and it really has to do with Banner’s attitude about who he is when he turns into the Hulk. And since the movie begins with the team together, the first thing we see is superhero Hulk, who has a level of cogency that makes him still useful and he isn’t just swatting things madly. But then, once the Scarlet Witch gets done with him, we get to see a vision of him that we have never seen before where he is completely out of control. And also clearly in a lot of pain. It was kind of beautiful to be able to go that far with him.”
Whedon mentions the legal issues surrounding a Hulk solo movie as well as that Hulk is essentially not a classic superhero comparing the Hulk to a werewolf story (interesting enough, the Gray Hulk in the comics transforms at night and is strongest during a New Moon - because of less sunlight - and weakest during the Full Moon - because of the strong reflection of the sun's light).
“Honestly I think it’s a legal thing. I think it’s because there’s other studio rights and this and that. It’s difficult. Hulk movies are very difficult because it isn’t a classic superhero story. It is more of a werewolf story, and finding a way to thread both of those makes if difficult. But I think it has more to do with the boring issues… because they love the Hulk and they love Mark as much as I do.”
Recently, both Whedon and Ruffalo seemed to tease the future of the Hulk, with Whedon stating it's going to be "amazing."
"The Avengers: Age Of Ultron" has May 1, 2015 release.