I've read much here about super-high ISO performance, incredible AF system etc... that are the true killer features. Well... depending on how they will really perform at real world in the hands of not canon testers. I think many of you saw high iso test shots that were really amazing and hope they were not with huge amount of post-pro from any of the CS5 guru-people
But you didn't mention digic 5+ processors that are considered to deliver exceptional exposure and color control providing great mid-tone contrast increasing overall image quality. I've read some comments as well as saw some videos from people that say "photoshop is not needed" with 1dx... I don't know how much truth is in their words but... it makes to think of smth
For real... I don't think that AF system and higher that 1d Mark IV ISO performance will force pro-wedding-sports-guys to sell there bodies and go for 1Dx
And, besides, they are the target people for that camera. That thing is deeper... increase in dynamic range and accurate exposure may be also one of the key features, and I suppose canon will rely on them when advertising because ISO is not enough (Nikon d3s or d3x has outstanding (read higher) working iso besides, so if canon whats to outsell them 2 points are not enough). If having 5dm2 with working ISO 6400 will you upgrade if you will be offered with the same, but working ISO increased to 12800? I guess not... unless you'll need it now and today or for free.
At cpn.canon-europe.com there is a great article describing both AF and AE systems, explaining many new features that will be introduced and much is said about image and color quality. Al in all I just want to say that looking at 1dx just like at increase in ISO or AF is not correct, but I may be wrong of course...
P.S. Don't blame me for Nikon:)