So, is there a banned list ATM? Are imperial aces legal for games using the official tourney rules now?
For competitive play, only the TIE Advanced is banned.
Just kidding. I don't see any "banned list" anywhere. I would think they have to publicize that, and they would only do it if there is a major release in the middle of the next round of tournaments. For example, if Wave 4 is miraculously released before the end of Regionals (or even if it isn't there will be promo copies of the expansions out there from the Imdaar event) they will ban them temporarily I think.
From the Tournament Rules
All Star Wars: X-Wing™ Miniatures Game components are legal for sanctioned play unless they are marked with the epic icon (ships with the epic icon ( ) next to the card title on the Ship card can be fielded only in Epic Play), or temporarily banned from tournament play (such as when a product is released in the midst of a tournament season).
So Aces should not be allowed in any remaining store championships.