I wonder how many people associate Sir Stewart as Xavier rather than Picard. I figure it'd be a generational thing, as Picard ran from 1987-2002, and Xavier from 2000-2017.
I remember after Star Trek (2009) came out, a bunch of fans were upset because they thought the movie effectively ended and negated the Prime universe (ie, it ceased to exist and none of it ever happened because Nero went back in time and mucked things up). There may have been other things to be upset about regarding Abramsverse, but that was by far the least (and stupidest) of it.
I really do want Q to make one last appearance. Yes, John de Lancie is old now, but young-again CG has come a long way, or they can play it off as "I look as old as you, Picard, to make you feel better".