We've had a few Mirror universe episodes in TOS, DS9 and ENT...but what sets it apart from every other alternate timeline someone visits? Like we know there are more than 2 timelines...there's the main one, the mirror one, all those timelines Worf visited that one time, the Enterprise C didn't get destroyed one, the future Picard experienced in All Good Things, the Defiant crashes on an alien planet and the crew forms a colony etc
Would every alternate timeline also have a mirror universe paired with it? Is there a point when the mirror universe diverged from the main timeline or was there never a shared history between the two timelines?
Reverend Meteor (do universes come in pairs?)
The Mirror Universe simply had more style. Uhura's thigh-high boots and exposed midriff, and Spock's goatee. And they had an Agonizer. Also, Kirk ascended to the Captaincy by assassinating Pike. Doesn't get much cooler than that. Every actor wants to play the mirror version of their character.
The other ones you mentioned were nice stories that no one was compelled to revisit. Although Enterprise kind of did their version of the DS9 episode where the met the other Enterprise that went back in a time warp and the crew had lived on another 50 or 100 years and had a whole other life.