That's true of any studio though...the script has to be approved by the people spending the money on it before it goes into production, superhero film or not. It's normal for there to be a little push and pull between a director and the studio. Painting Wright as the "stubborn artist unable to compromise" is no different than painting Marvel/Disney as the "big, bag studio restricting creativity" at this point. There's always two sides to a situation. I think it's fair to say that Wright was probably originally going to have more creative control over this when the project was in its early stages. He's the one who came to Marvel with his vision for it in the first place, when they had no plans of making an Ant-Man movie.
Just a note: Marvel approached Wright, asking him if there was a character he wanted to do, not the other way around.
The reason I give Marvel more credit for restricting creativity is because they've shown that they're very much capable of that, from Iron Man 2 to other artists/creators they've ticked off. Marvel's goal is to build a universe, and sometimes that means making a lesser individual film so that you can set up something for later. They need to hire artists who are prepared to make worse films if that means that a future film might do better, even if that artist isn't involved.
If James Gunn actually directs Ant Man, noone will be able to use the "Marvel doesnt take chances" comment. GOTG was taking taking a chance and it sounds like they love it.
Who has said Marvel doesn't take chances?
Also, James Gunn actually started with more of a cookie-cutter film, and Whedon, who is in a position where Marvel is flexible to him more than the other away around, told him to make it less cookie-cutter.
I really dont get why theyd take a chance of driving Wright away like this. You dont screw with a filmmakers script unless its just plain wrong. It seems to just cause more problems for everyone. I guess it really had to be fixed before it was made.
That's not true. If you are building a Universe, and you need to put in some Phase 3 stuff, or you need characters to have a status quo at the end, even if that goes against the director's vision, or the theme/message of the film, then you change it, no matter how awesome the script/film is.
For Marvel, it's a better business decision to have an Ant-Man that's good that help sets up Avengers 3 than an Ant-Man's that's great that only has some one-liner connection to the MCU.