Do you have a source for that?
Let’s face it her character was a little underwhelming. That’s mostly writing not acting. She seemed totally charming in the role, but the role just wasn’t very good.
This promises to be a much more interesting role. I imagine this has been on the cards for a while, and that it explains the voice work in Endgame and the red carpet appearance. Let’s not pretend this isn’t a great result for Marvel.
Also, it seems like Waititi is an Aaron fan, based on this and some of his comments in the director’s commentary for Ragnarok. This is pretty much perfect for the MCU IMO.