1) This "rumor" to me is the death knell for a D400. The D7000 is a generation newer than the D300, and yet they are upgrading it first? So it will be 2 generations newer? It lloks like the D7200 will be the top of the line DX camera for the forseeable future.
2) I would love to have the 51 point AF system,...but I'll probably jump if all the D7200 has is 24 MP and one stop of better ISO performance. Since this is probably a new sensor (or at least tweaked from the D5200), I would guess we can expect one stop.
3) I echo above,...the learning curve from 12MP to 16MP was steep for me. But, I think a lot of it was my unrealistic expectations of what the AF system could do with my amature lenses and the weaker (vs the pro bodies) on-board AF motor. Hopefully, if this is the top of the line DX body, they will give us a more robust AF system.
4) I can live with 6 FPS, but please give us the option to increase FPS with the vertical grip. Please. Though I doubt they will, unless they give us the 51 point system.
5) One generation in DSLR's is HUGE. The D7000 is an order of magnitude better than the D90/D300 in low light performance and cropping resolution.