Sadly, I think there'll be backlash against her any way you look at it. Excluding the salt from not getting their most-wanted character, people will complain because "she doesn't fight," "isn't cool/too cutesie/girly," "comes from a baby game," "is too new/muh seniority," etc.
Honestly, most people overlook how big she is in Nintendo now. Animal Crossing is a lot bigger than most people give it credit. It's outgrown fan favorites such as Star Fox, F-Zero, or even Metroid, but because of it's non-action focus, most write it off as some little side game. And with her as the defacto face of the series, she holds more weight than most of the castle already included. If you don't see her getting in, you aren't paying attention to Nintendo.
