Again, there is speculation that Q will appear in the final episode. Part of me hopes he doesn't though. The basic problem is you just know that if Q gets back in contact with PIcard he's not going to leave well enough alone - he's going to do something tell him that when he finally kicks the bucket he's going to come to the Q continuum or something. And it's going to take a lot of the tension out of the show as a result. Or even worse, just magic Data back into being.
I was thinking about this. The only acceptable Q fix ending really, if I were doing it, is to have Q switch Picard with Data on the Scimitar, after Picard requests it. That might just about work.