I should have waited to purchase mine smh. The price of this camera seems to be dropping quicker than a brand new vehicle. Almost 15% since release.
And since the 6d "entry ff" rumor imho the 5d3 will continue to drop, since a lot of people wanting a ff body but not the old 5d2 will stop buying the 5d3. The early adopters willing to pay no matter what now have got it, so that's it for the $3500 price tag.
The 5d3 be very good for some applications (wedding/event). But many folks don't need the added gimmicks but are set back by the lack of sensor improvement over the 5d2.
And the one thing really setting the 5d3 apart from the competition is the af - but it's a mixed bag even apart from the af point highlight problem in servo: few people need this massive af point coverage, but might do better with less af points that are geared for non-f2.8 lenses, too (even my 60d has cross points on the side for the 70-300L, the 5d3 puts it in a group with only horizontal points to the sides).
The main advantage I see with the 5D3 over the 5D2 is the auto ISO in manual mode and this has really made it more of a sports camera now than just a wedding/portrait camera. You can now shoot sports with spot metering with a fixed aperture and minimum shutter speed. This would be unheard of with a 5D2. The AF sensor issue you talk about is true, don't get me wrong, but there are far less total AF points on the 60D and 5D2 that those cameras don't really factor into serious sports shooters' thoughts. In other words, the 60D does offer those points on the edge, but the 60D has less accessable points overall. Also, the "sides" of the 60D's fram is also 1.6x the distance of the sides of the 5D3. None of the advantages of the 5D3 over the 5D2 are gimmicks at all if you need the 5D3 for things that the 5D2 can't do. It's a matter of what YOU need the camera for. If I were only doing weddings, I probably wouldn't have spent the money on the 5D3 and just had a pair of 5D2's, to be quite honest with you.
My point is this. If we would see a 6D or something come out, it is very difficult to predict what type of camera it will be. Could it be an 18 MP APS-C camera? Sure, but maybe it will have an auto ISO in manual mode as well. Sort of an APS-C 5D Mark III with 18 MP? Or not. Who knows.