>1. Compatibility with the MB-D10 grip >2. Compatibility with the EN-EL3e battery
Is it likely that anything Nikon releases will be compatible with either of these? I assumed, granted without giving it much thought, that the new, higher capacity battery, would be a given in any new camera coming from Nikon. The P7000, D3100 and the D7000 are all using a new battery (the P7000 and D3100 use the same new one, the D7000 of course has a higher capacity one). If nothing else a new battery would also mean a new grip in all likelihood.
I can see how this is a significant deterrent to some who have a collection of EN-EL3e batteries (they are not cheap). On the positive side the newer battery gives you nearly 2x the shots per charge so that would mean you would need 1/2 the number of batteries you currently have.
I have to say, the one disappointment for me in the D7000 is the grip. Cheaper third party grips that will be eventually released, notwithstanding, it is a pricey addition that doesn't increase performance. If you actually buy the Nikon grip and batteries for it, that is around $400.00, which does get you 1000 extra shots (give or take) and makes portrait orientation photo taking a tad easier for some. Still, it seems like Nikon purposely didn't use that extra power for anything functional so they could leave the 8-10 fps realm for the D400.
p.s. There appears to be reason to believe that the D7000 would focus as well if not better than cameras with the current 3500DX sensor. The loss of some AF points may have some impact, but the distribution of AF points for the 4800DX seems very similar to the 3500DX. Additionally, with 1300 additional CCD contrast sensing elements, low light focus should be spot on (no pun intended...well okay maybe a little).