I have been wondering would a star trek show based in the mirror universe work.
Um, no. Just, no.
Mirror, Mirror worked fine as a stand alone episode.
In a Mirror Darkly was great fun and great fan wank: tying both Mirror, Mirror and Tholian Web into the Enterprise show. It remains one of my favorite Enterprise, and indeed Star Trek, episodes.
DS9, while it was arguably the best overall Trek Series, at least for me, just totally dropped the ball on the Mirror Universe. Not one of the mirror universe episodes hold up for me. I think they are all horrid.
Meh. It would very quickly devolve into Nazis-in-space with the racism turned into species-ism.
Not to mention, when you make an entire series around a "mirror universe," by default, it becomes the prime universe because it is the universe being featured.