I’d love a series about the fall of Ben Solo, it’d definitely be more dramatic than a book about it.
As for the Celebration surprise(s), someone mentioned earlier the possibility of it being a Lucas appearance. That would be fitting, and I don’t think anyone said the surprise would be any kind of announcement. If anything, the big surprise being merchandise of any kind, including a new home media release, would probably get an underwhelming “making the fans buy the same movies again” response, OOT or not. That doesn’t sound like a fitting enough surprise for such a huge panel.
I’m starting to think you’re right, and that we’re probably getting our hopes up for no good reason at all.
If it ever happens, it will probably be an out of the blue announcement when we least suspect it just like the GOUT was.