As for the other movies you mentioned, different tone of movies (one being a kids/family movie) than what the MCU has been going for.
I'd hardly say the MCU is going for a single uniform tone. Thor
and Captain America
felt very different from each other and from something like Iron Man
. And next they're doing Guardians of the Galaxy
, whose cast includes a talking raccoon and a sentient tree whose dialogue consists solely of "I am Groot." Clearly they're not afraid to mix things up a little. The goal isn't to make everything the same, but to create a broad universe that includes a range of different styles, character types, and even genres. Remember what Whedon said about the Avengers? That these characters didn't belong in the same movie, that it was the clash that made them interesting? The Marvel Universe is one big multi-genre mashup.
Aside from all of that, Ant-Man is also a bit of a jackass so I don't know how they're going to get people to root for him in a movie.
Two words: Tony... Stark.