There is a wonderful discussion about this subject on You Tube featuring Zack Arias, Gordon Laing from Cameralabs.com , Frederick Van Johnson, Trey Ratcliff plus others. It's very interesting. I've been waiting for an announcement from Canon on the upgrade for the 7D, but now I don't know. Maybe I should wait to see how the mirrorless cameras evolve.
I'll keep you informed. You can find the discussion here.