Originally Posted by metaphysician
As people have said, Planet Hulk really doesn't fit the MCU. Nobody really wants to banish the Hulk, nor have they for some time. And Banner has *more* control over the Hulk now, not less, to the point where he can actually act as a superhero under sufficiently extreme circumstances. It would really, really come off as out-of-nowhere and unjustified.
The only possible exception would be if it weren't a deliberate banishment, but an *accidental* one, resulting from a science experiment gone bad or such. Make it a bit of a planetary romance where both Banner *and* Hulk have something to do.
It seems to me that people are just assuming that because Banner was able to direct the Hulk in a single battle against a common enemy, he is all of a sudden a giant green boyscout.
It was one transformation that followed hard on the heels of the Hulk rampaging on the helicarrier almost killing BW and putting a whoopin on Thor. Yes Loki released the beast but after that, the Hulk just did what Hulk does . . . SMASH!
Well if you want to disregard TIH and the Hellicarrier sequence, yeah, he's a great guy. However even when he was in a "controlled state" in the comics, teammates and friends were still wary of when the Hulk might bust loose again. It created a barrier which prevented the character from being fully embraced in any team.
THE most compelling aspect of the character is the struggle with the inner-monster. Yes, he was cast in a more heroic light in the Avengers but the underlying theme was that Shield and his teammates were concerned and uncertain of his stability. Not including these conflicts is essentially neutering the chaotic nature of the character and removing a potentially dynamic story element.
It's not like General Ross went away or anything. One uncontrolled transformation brought on by pain, fear or rage and some collatoral damage (the Hulk's bread and butter) would be sufficient to start the hunt again.
I say make the Hulk an antagonist is the next Avengers! The Hulk CANNOT be controlled. Directed yes. Controlled NO WAY. Furthermore, the Hulk does not WANT to be controlled.
I am not saying to make him evil, I am saying make him the Hulk.
Banner slips up in a moment of weakness and the Hulk busts loose, much like the Helicarrier scene. He uses too much force in dealing with some threat. A town is damaged, innocents are hurt . . . whatever. The point is, it would only take an "unsancationed" transformation to set off another manhunt and rampage. Not really a stretch that The Avengers might assemble to neutralize their brother in arms before he is confronted by the military's Hulkbusters. However, they are all forced to unite in the face of a greater threat. Unfortunately after the threat is defeated the government is able to capture the weakened Hulk and despite the Avengers violent objections they are able to launch the Hulk into space.
Bring on Planet Hulk!
People saying Planet Hulk doesn't fit in the MU need to look back at the Thor boards when "fans" were saying the God of Thunder didn't fit in the MU.
The incredible success of The Avengers that employed SO many varied scifi and fantasy elements is a single movie proves that NOTHING is off the table when adapting these stories.