Originally Posted by Crimson King
It won't detract from anything if it fits with the story. And you can't tell the IM3 story in its own world. That goes against everything they've built with the MCU.
It would definitely detract from the story (and the MCU as a whole) if Janet Van Dyne made her debut in the MCU in IM3 practically sexually assaulting Tony Stark.
That would be a supreme disservice to the character (Janet is *nothing* like that), and would likely be perceived as intruding on Edgar Wright's territory, since Janet reasonably should make her debut in the Ant-Man movie.