The winners of this Next Fest for me so far have been:
Aero GPX
Someone finally made a new F-Zero. It just wasn't Nintendo. It feels like a proper modern version of F-Zero GX, but I don't think it's going to have online play. At least it'll have local multiplayer, which is far more important to me in a racing game.
Diesel Legacy: The Brazen Age
This is a 2v2 fighting game that I'm far more likely to play than 2XKO, since that one will almost certainly have no true offline mode and require installing a rootkit to play. No thanks. This one operates on 3 lanes, so all four teammates can be playing simultaneously. The art is gorgeous, the netcode feels great, and I could see myself getting really into this. The only problem is I don't know all of the game's mechanics, since the tutorial for the game really only teaches you about the 3 lanes. I can figure some stuff out in its best-in-class training mode, but without banging my head against the wall, I won't figure it all out. I'm sure the tutorial will be more robust at release.
Tactical Breach Wizards
This is probably the most high-profile of the three, so I don't need to say much about it. It's a tactics game with magical powers and a good sense of humor, from the maker of Gunpoint and Heat Signature. I'll be playing the full release for sure.
Also, I'd recommend Big Boy Boxing, a game inspired by Punch-Out, which I've played at PAX already, and now I'm just waiting for a release date. It's that good.