Sounds like a solid update, one that would tempt me to get, more for the AF than the rate.
MP count wise, you have to wonder if they're going to jump up to catch Sony/Nikon, or are they going to follow the 5D series lead and have a minor bump to say 19MP? Keeping the MP down would help keep the fps up, and take some pressure off whatever size buffer they put in.
If this happens then finally things are looking up for those who need more reach than the disappointment of other recent high end bodies.