I'm hoping that the next lockbox will offer mirror Defiant & Prometheus... so that we have two cruisers, two sci, and two escorts. I wouldn't mind checking out a mirror Prometheus.
A cool console that might work for the mirror ships, would be something that opens a rift to the mirror universe, from which mirror universe ships can come to your defense temporarily.
There are already two mirror universe DOFFs that you can get from the colonial missions in the D'kel cluster (I think), but adding some mirror universe BOFFs would be very nice.
I like the idea of playing as your mirror counterpart- or maybe like a 'trading places' kind of mission where you have to pass as your mirror self. I don't know if it would be possible to have a meeting between you and your mirror self, with some minor costume changes, but that would be very cool.
Not to knock the idea or anything, but what could be Mirror about a Bird of Prey? They have three consoles slots for each sci, tac, and eng, and all universal BOFF slots. Its completly open as to how you want to equip it.
the only thing i would want is a Mirror Galaxy Class, featuring the Hull HP, BOFF & Console layout of the D'Kora, Galor or even the Regent Class but with the looks of the Galaxy Class.
It could come with the Galaxy, Envoy and Celestial ship parts as well as with the Venture and Monarch for those who have bought the appropriate ships in the C/Z- Store.
I think it would be a nice gesture to all TNG fans out there who are frustrated and dissappointed with the Galaxy class as it is in the game.
Other than that... i wouldn't want to play a "mirror" universe captain & crew they are just crazy fascists (there is absolutely NOTHING cool about that).
The mirror universe would be the perfect enemy to fight for the real federation.