Almost all fighters had mirrors.
Air Warrior had mirrors and that didn't slow the game down.
IL-2 has mirrors, and that doesn't slow the game down. (There is an IL-2 film out that shows the use of mirrors on a P47)
If Aces High can have 3 dimensional external views on bombers, I don't understand why mirrors would be such a big deal. And I don't understand how Air Warrior could do it, and how IL-2 can do it, but our graphics guys, who have to be better than the others, can't get it done.