Let's start with this nonsense talk of Planet Hulk/World War Hulk story arcs. As a dedicated reader of comic books those two stories were incredible but as a film I believe they are running a risk of upsetting people. The fact that all of the progress the Hulk has made as a character in a cinematic sense will be for nothing and he will be backtracked to being just a monster again. Do I think that Marvel fanboys will like it? No doubt whatsoever. But the kids that fell in love with Cap, Thor and Iron Man after their respective solo films became Hulk fans after watching the Avengers. It is those kids that are going to be utterly heartbroken to watch a bunch of the Hulk's "friends" turn their backs on him and send him into space because he doesn't fit in their vision of the future. He has finally gotten to a point that he can control the beast and now he will do something so unforgivable that the only course of action is exile? In space? It is a move like that that will turn Hulk fans against The Avengers.
The other problems are going to come from unknown properties (GOTG, Ant-Man,Dr. Strange.) They took a major risk with the Iron Man, Thor, and Cap movies but it paid off. It paid off very well. I believe however that this next batch of unknowns has Iron Man 2 written all over them. If history has shown us anything it is that the right moment, the right man, and the right movie can pay off very well. For proof of this just look back to 2008, RDJ, and Iron Man. That formula could work for Dr. Strange but I just do not believe that can work for the likes of Ant-Man. What makes Hank Pym such an endearing character are his many flaws and screw ups. It remains to be seen how general audiences and kids in particular can embrace a wife beating, cowardly quitter such as Dr.Pym.
As far as GOTG, it was hard enough explaining to people who the purple guy at the end of the Avengers was let alone a whole cast of unknown cosmic characters. If there is not major ground work laid on various cosmic aspects of the Marvel Universe such as, S.W.O.R.D., the Nova corps. or the Kree empire this has potential to be a dismal failure and could put Marvel Studios in a financial crunch and could very well be the ruination of all they have accomplished.
So in conclusion, whether they can keep this ball rolling remains to be seen but I truly believe that Kevin Feige and company need to tread lightly while addressing ol' green genes so as to not step on toes and dreams. I will remain vigilant and hopeful for my beloved MCU as any good fanboy should. Until next time, this has been your friendly neighborhood Inkslinger bidding you adieu. Peace.