Earlier quoted context omitted.
Crimea could turn into an independent, mostly Russian speaking, fully demilitarized country living off tourism. Possibly joining the EU later. I bet they would be much richer than today. Being a part of Russia sucks from the economic point of view. IDK if Crimean Russians are so nationalistic that they would rather live in a semi-starved, heavily sanctioned, economically isolated country.
Why can't they remain part of Russia like they historically were (well, I mean since Russia took over form the Tatars, of course) and seem to want? It's not because Russia has taken Crimea back in a rather cavalier way that they should be split again just to weaken Russia. This can only perpetuate resentment and problems.
Having Russian military bases on their south flank is a major security problem for Ukraine.