What if the Marvel Cinematic Universe had all their character rights, including the X-Men, Spider-Man, Fantastic Four, etc. They don't have to share these with any studios (Like the they do with Universal with The Hulk/Namor and Sony with Spider-Man), they own the rights and have 100% creative control over them. How would this have changed the MCU? Would it have been similar to how it currently is, or would it be completely different?
So Historically, I should give explain how this could all happen. Let's say Marvel in the 1990s when it was about to go bankrupt do not sell their cinematic rights, because they notice how superheroes movies are getting more popular and want in on it. So they make in a deal with a big entertainment company (It could be Disney, Time Warner, 20th Century Fox, etc) that they will buy Marvel, while agreeing to let their Marvel Studio make movies, as long as the company gets some of the profit. This would probably mean the MCU would've started a little earlier than it did before, since Kevin Feige would've not pitched the idea from the MCU right after this deal came about.
So with all that out the way, my theory is that the MCU would've been kind of different at the beginning. With the Universe starting off with an X-Men Movie, and being followed up by a Spider-Man and Fantastic Four movie. These would probably get a couple sequels, but I think Marvel Studios would still want to make The Avengers, and would make the Iron Man, Captain America, Thor, Hulk movies as well. The MCU would be pretty similar to how it is now, except the universe would be much larger and I imagine crossovers would be more common and maybe some plotlines would be changed.
For example, Marvel would've probably used Mutants to explain Superpowers in Agents of S.H.I.E.L.D. a lot more, as opposed to being Inhuman or getting powers for other miscellaneous reasons. I also think Dr. Doom would have been the main villain of the first Avenges movie, as opposed to Loki, since Joss Whedon stated he originally wanted to use him, but couldn't because he is tied up to the Fantastic Four rights, which Marvel doesn't have!
But that's just what I think, I'm sure a lot of MCU experts on this Wiki have some ideas, and I want to hear them. Please, share your ideas in the comments section! Good day! :)