Maybe. I dont think the translucent mirror thing is a good way to go for pro bodies though. you looks like a third stop of your light right there (or am i wrong?).
It's two thirds: http://en.wikipedia.org/wiki/Canon_EOS_RT ... however, with a good sensor and a fast lens it doesn't make a difference in ok light. The thing is: I once owned an non-digital Canon RT with a fixed mirror and it was the greatest camera I ever had! With a fixed, translucent mirror, you can actually see what you shoot (no blackout) and this makes tracking *much* easier, and the response time was stellar. I only needed to lightly touch the button and it had already made the picture before I knew it - with my current 60d, there is a considerable lag between "butterfly sits on flower" and "camera makes picture of flower without butterfly". A 7d2 with a translucent mirror would be the killer for wildlife shots.
Great point. Would be good for certain things i guess. But for my low light work, i would hate to have a two third stop handicap. Thats almost the difference between shooting at 6400 iso and 12.8k iso.