My wishlist of future content:
B-Wing vs XG1 Starwing (AKA Assault Gunboat) or B-Wing vs TIE Brute
Alternate models for different weapon customisation, like for example a death-star like laser dish on the portside pod of the TIE bomber if it has the composite laser weapon. Y-Wing already has this for aux ion cannons.
Fairing options for the y-wing for some clone wars style. Similar alternate skins for the other fighters, if good canon options can be sourced, or good designs can be created.
Modding support for single player, so that community created missions and campaigns can be added, and community created ships can be imported.
More capital ships and missions for single player at least, multiplayer if possible, that allows more variety in the fleet compositions of fleet battles.
Maybe later E-Wing vs XG1 (if the TIE Brute is selected above) or E-Wing vs TIE Avenger.
Single player mission in a TIE Defender