The mirror doesnt have to be placed on the screen at all. It could be displayed on its own when pressing a key.
I'm seriously against this.
If there is a mirror which would be used as a means to look straight back in the game, then it should be implemented with all its disadvantages. The small size, the shakes and blurs, and the very teeney tiny bit of detail depicted which just might allow a pilot to catch glimpse of something behind him.
Otherwise if a separate 'mirror view' will put up a screen which lets you see everything behind your 6 in full-size, sort of like how EAW used to, then we might as well ask HT for transparent cockpits too.
Personally, I'd like to see mirrors in the game as well, but if we're not gonna have them the right way, then we're better off not having them at all.