Gameplay is more arcade-y than past entries- which is fine- but the story is goes off the rails in a bad way. Halfway-in the plot frays into a bunch of different threads that don't really go anywhere and none of which are terribly compelling on their own. Your squad also may as well not exist, in both a gameplay and narrative sense- even with pictures to go with their radio chatter, they all kind of blend together, and everyone's personality is eventually replaced with simply praising you after every single kill- which is understandable when you see six of them struggling to take down a single enemy fighter.
I don't mean to be so harsh on what is a perfectly good game, but I'm afraid people will start with 7 and dismiss the rest of the series out of hand. The PS2 trilogy are legitimately some of the best games on the console, which is saying something. I would highly recommend going back and giving them a shot if you enjoyed AC7 but left wanting longer missions and a real story.
Hopefully they get re-releases on this new engine, because it manages to be both extremely beautiful and well optimized.