Well, canonically Strangreal as a whole is moving towards a globalist policy, which greatly opens up the chances of playing as a pilot from and/or taking place in one of the lesser-known countries. It seems like they're trying to connect the current timeline to AC3, whose canonicleness (that's a word now) has been in limbo for quite a long time.
Gameplay-wise, chances are the silly tropes and one-man-kills-all combat style will still be there, as those are a big part of the Ace Combat identity. Replaying AC5 and Zero did make me aware of how useless your teammates are in 7, with the odd exception of the DLC missions. More competent squadmates and/or the return of the command prompt ingame would be very welcome.
What I would really like in the next game is co-op (which I'm amazed isn't a thing, the games seem made for it), and a much more robust and better-balanced multiplayer. AC7s multiplayer is definitely an afterthought (not helped by the chaotic development), but it is still a fun and mostly-functioning afterthought. The potential for a really good multiplayer mode is there, and after watching a whole bunch of footage of Ace Combat Infinity, I think that Bamco and Project ACES could hit a major home run if they give multiplayer a good amount of effort. Competitive PvE, PvP air battles, co-op campaign and the like would be very worthwhile additions, and imo would fully utilize the potential that these games have.