I'd expect a relatively minor update, the other models are still catching up to the 7D features. Probably nothing a current 7D owner would want to upgrade for.
New Battery, new video features, larger LCD, digic V, and a lower MP sensor.
I don't think so. Remember that the 7D will be three years old by the time Photokina rolls around. The three year cycle makes me believe Canon will want to give current owners an incentive to upgrade. They learned the risks of incremental upgrades with the 50D, I doubt they make that mistake again. And, since the market has matured so much over the past few years, (meaning slower growth) I'm sure they realize that they can't just rely on Rebel and 60D upgraders.
They don't want current 7D owners (like me) sitting on our wallets. Question is, how best to get us to pony up?
I'm guessing they will concentrate on improved image quality, ISO performance and auto-focus improvements.
The on-camera flash has a couple of problems that need to be fixed (contacts too easily bend and jam the flash shut and the flash itself overheats way too easily -- making the infrared trigger useless) But, those are about the only major issues that I am aware of.
Possibly some video improvements, but unlike the 5DII, I don't believe the 7D is viewed by Canon as a top video DSLR. I'm no video person, so I certainly could be wrong about that.
We know Canon is watching very carefully how the pro-market reacts to the death of the APS-H sensor. (Repeat after me: Canon will not put an APS-H sensor in a 7D. Canon will not put an APS-H sensor in a 7D...)
But, they could decide to sufficiently upgrade the 7D to target pro-sports and wildlife shooters. Either in a base model or in a 7D-X.