Personally, I think the 7D Mark II will be an awesome camera, much better than any other APS-C camera. But let me qualify that opinion.
I expect it's low light/noise performance to be considerably better than the aging 7D -- but only slightly better (or on par) with the 70D's. I don't expect it to come anywhere near any of the full-frame or APS-H cameras in that regard. It'd be NICE if it did, but anyone who's holding out for a major improvement in low light should really just pony up for a 5D Mark III (or a 6D if they don't need fast action type photography). Or a 1DX if they can afford it (or a second-hand 1D Mark IV).
Where I do expect a huge improvement is in performance for wildlife, sports and action shooting. In particular, burst rate, buffer and AI Servo AF improvements are going to be the main items for this camera.
I think we can expect a much better frame rate of at least 10fps and possibly even the rumoured 12. In addition, I think we can expect to see a large buffer to take advantage of that frame rate. Expect it to at least match the post firmware 24 RAW buffer of the current 7D, but I expect it to do even better--possibly 30-35 RAW shots. Indeed, that would be almost a MUST have with the increased frame rate. I'd like to see the 12fps, but 10fps would certainly be a worthy improvement over the current 7D's 8fps or the 70D's 7fps. To those who don't think there's much of a difference between 8fps and 10fps, those extra 2 frames can make the difference between capturing the entire bird just as it leaves the branch, and getting a decapitated shot with just the wings and feet! And 12fps would be even better! Not to mention capturing much more of a stunning sequence, such as a canon shot or explosion at a War of 1812 re-enactment, or any number of other scenarios.
The area where APS-C cameras really need improvement is in AF. The 19 point AF system of the 7D is a pretty awesome piece of tech, but it misses too often compared to the AF systems of the 5D Mark III and 1DX, or even the 1D Mark IV. The 70D has gotten an improved version of the 7D's 19 point AF of course that is reputed to be more reliable than the 7D's system and that's fine for the xxD line, but the 7D Mark II needs a FIRST CLASS AF system to justify its premium price. Earlier rumours suggested it would get a variation on the 61 Point AF system of the 5D3/1DX and later ones suggested a revolutionary new AF that would be shared with a new 1 series camera. Either of those options work for me! The main thing it NEEDS is superior Servo tracking of moving targets, the same way the 5D3 and 1DX do. The current 7D struggles too often with moving targets like birds, even when you hold the active AF point on target.
I love my 7D, but I'm REALLY excited on the expected/rumoured improvements we can expect from this camera. I don't think it will just be some warmed over 70D with different ergonomics. That would be an epic failure if Canon did that after so much anticipation. I also expect it will have a DPAF (probably 24MP) and enhanced video, which is all good. It will have cleaner output than the 7D, but probably on par or moderately better than the 70D. Where it will mostly shine is in world-class speed and AF capabilities.
Time will tell!
