Why I think a World War Hulk movie is a terrible idea...
Yes, I know this is a very old rumor. But to the best of my knowledge it hasn't been debunked yet. We all heard this rumor a month or so ago, many of us jumped for joy, while others (like myself) rolled our eyes and thought "oh...crap, don't do this please!" I'm not trying to debunk the rumor here in this article, I'm just stating why it's a bad idea.
Reason #1: Too many characters involved

First of all there is the fact that the World War Hulk storyline included a ton of characters that won't be able to fit in a single movie. Six heroes on screen at once was already a heck of a job for Marvel and Whedon to pull off. Even then some characters weren't given their due screen time (Hawkeye for example), then there is the fact that some of the characters involved can't be in the MCU. Because Marvel doesent currently have the rights to the X-Men, and the Fantastic Four. Both of which are key to the story of World War Hulk. But really to use that many characters on screen at once would be near impossible. It'd turn out to be a crappy film that gets made fun of all the time...akin to Elektra or Green Lantern. Also that the MCU would need years to introduce all of the characters involved, think about Doctor Strange, Sentry, Hercules, Mr. Fantastic, Black Bolt. And a ton of others, if it was to be done properly. Than it'd be around 20 years from now till a World War Hulk movie actually comes out. I think there are just way too many characters involved in World War Hulk, and many of those characters Marvel doesn't even have the rights to. It's just crazy for them to put 20+ super heroes in a single film, it's insanity to try and do it. THAT much action is just too much, too many characters to be able to pull it off well, anyways that is the first reason why I think World War Hulk is a terrible idea...
Reason #2: Too much money
Secondly, there is the dilemma of money. IF Marvel somehow was able to pull all of those characters required into a single movie, how much money would it cost to hire all of those actors and to produce all of that animation in the battles and stuff. It'd be a crazy amount I'll tell you that, to produce special effects for everyone from Hulk to Doc Strange to Iron Man to Reed Richards to Sentry and beyond...it's just way too much special effects and even Disney would be hard pressed to take that on. They would probably need a vast portion of Disney's fortune to actually pull it off, it just seems too hard to do, so I think it's better to just not do it in the first place. That is the second reason why I think a World War Hulk movie would be a terrible idea.
Reason #3: It would destroy Hulk's image and reputation in the general audience

Lastly, there is the fact that producing a World War Hulk movie would ruin Hulk's current reputation. It's taken three whole movies to finally get Hulk to where he should be...as a hero. In the eyes of the general audience, Hulk is no longer a mindless monster...he's a SUPERHERO....not a mindless beast, not an anti-hero, a HERO. That's the way it should be, it's taken this long to show Hulk's heroic side, and it's taken three movies to do so. And Hulk's popularity is at it's peak at the moment, so why would it be a good idea to back track on that now?How would having Hulk as a villain in an Avengers movie benefit the character, or his popularity? It would only hurt his rep, because they've finally gotten him to the point where he's a hero. To turn back on that now, and make him a villain is just a flat-out terrible idea. Plus, you know what happens at the end of World War Hulk don't you? Hulk gets defeated, is imprisoned. He's one of the most popular characters out there right now, and to have him lose and be imprisoned would either kill his popularity or just cause all of his fans to hate all of the other super heroes, which means Marvel loses a chunk of their audience. How many Hulk fans would honestly want to see him get defeated and imprisoned after we FINALLY got to see his hero side? Honestly? How many? Anyways, that is the third reason why I think a World War Hulk movie would end as a terrible film.
In closing, making Hulk a villain after he finally got to show his heroic side. And him being defeated and imprisoned, is not going to do any good for the MCU. Or the Hulk, or his fans, it's going to hurt his popularity...Hulk is my favorite Marvel character, to see this done to him would hurt me, honestly...this is a bad idea, c'mon Marvel we've been doing great so far don't ruin it now with a crap movie...
Anyways thanks for reading, please leave feedback in the comments. And express your own opinion on the matter.