Being a pretty big Sega fan from Genesis to Dreamcast, I'm seriously hoping that this isn't about Xbox exclusive anything. Sega has finally got some traction back from being pretty horrible over the last 18 years or so. Sonic Mania, Shenmue 3 and Streets of Rage 4 show that Sega's IPs can still be good. They can still be fun. Taking those IPs and making them exclusive to anything other than a Sega system would be pretty well bulls**t. Thus, I'm hoping it doesn't happen.
If they were to try a Game Gear successor with say.... backwards compatibility (unlikely), many of their IPs on it, etc.... I would probably be on board. That's saying something considering how badly I got burned with the Vita. I swore off handhelds after that. Of course, this hypothetical handheld would have to do quite a bit right.
My guess for what they are going to be announcing is probably something along the lines of Seaman 2 Fish Guy's Revenge. Coming to a console near you this fall. Hoping for something more like a division within the company being made specifically to bring their IPs back to life similarly to Sonic Mania and Streets of Rage 4. Say with games like Comix Zone, Ecco, etc.
We'll see, but I don't have much faith in them.