I toyed with the idea a few years ago, purely as a thought experiment, of reworking “The Cage” as a Mirror Universe adventure. My thinking went something like this–
Suppose that the vision the Talosians gave Pike of himself as an Orion slave trader was, roughly, the person Pike was in the Mirror Universe. Then perhaps the vision the Mirror Pike would receive would be of the Pike that we know, and just as our Pike was horrified by seeing his secret desires made manifest, so too was the Mirror Pike horrified at seeing his nobility brought to the fore, even if only in an imaginary setting.
The problem I had is that I could never come up with a workable reason for why the Talosians would let Pike go, and while I think the Enterprise could have laid waste to Talos IV, why wouldn’t Number One simply leave Pike there to his own devices, and take command of the ship for herself?
As I said, it was purely a thought experiment. That’s the trouble with so many of the adventures we know; if they happened in the Mirror Universe, very few of them wouldn’t be solved by Kirk with a phaser salvo.