28MP sounds great. Not too high as to keep FPS high and files sizes reasonable, but a decent increase for better resolution.
9FPS also sounds wonderful. That's a big increase over previous generation. 9fps really moves it into the fast category, rather than 5-7 which is now considered medium.
4K? I could care less, but it will be a must for Canon to avoid being thrashed on the net for the next 4 years.
ISO improvement would be welcomed. Hopefully it will go up 1 more stop for native ISO.
Dynamic Range, ah...the big question and a major sticking point for many haters and Nikon trolls. Hopefully there will be some increase there. I'd be surprised if they could catch up to the Sony sensors in one generation. But either way, not that important - Canon has as good or better DR at higher ISO as proved by DXO. And as stated ad nauseum, being able to crank up a lower ISO shot 4 stops is great for techie-geek wow-factor in post-process pixel peeping, but it still results in a bad photo and isn't relevant for real photography. More DR is better, but there's other features that trump it.
Autofocus - The 5D3 already has an excellent system. Hard to significantly improve on that. Improve yes, but big leap? Unlikely. I'd expect either the same 61 or the newer 65 point system but with all cross type, more dual cross type, more intelligence and probably dual pixel also.
Announced in late 2015? Then released later than that. Add in the backorders and mass rush by bloggers, pros and others - this camera won't be in somewhat normal stock til mid 2016 at best. With that kind of demand, unlikely to see it budge even the slightest from near MSRP prices til maybe the Black Friday sales of Nov. 2016 at best, and I imagine the sale / rebate price will be minimal.
So, those interested will likely have to wait about a year from today if they're on a preorder list and pay MSRP. This could change if Canon wants it released by this Christmas season...I doubt it.
Makes the 5D3 look so much more attractive for a while