I think you share a request from a lot of people but it might be unrealistic to expect much better high ISO performance from DX. The D7000 was quite a breakthrough and is not too far, about 1 stop, from the ideal or theoretical limit. One way of getting more low light performance is to go to higher pixel count and average out noise by downsampling which works so well with the D800. All Nikon cameras after April, if the rumor is correct will be 24 or more, except for the D4.
As it is, Nikon's entire camera line from entry level to pro has better dynamic range and less artifact than any Canon ever made. The sensor in the D3200 tests better than the $6000 1Dx and every other model ever made in that line. Yet, Canon owners are regularly getting images both for hobby and professional assignments that are great. Maybe the creativity of the user is more important than gear after all.
Very few people have outgrown the capabilities of the D7000, although many of us upgraded for the sake of upgrading, which is a bad habit most of us get into in some field.
I did a shoot Wednesday night with both a D7000 and D800 and both did all and more than I could have asked of them. Ironically, since the D7000 had the 70-200 mounted and the D800 had a 24-70, the most requests for copies of individual shots were those from the D7000. That I was, I am sure, because the telephoto was used for head shots which turning out like nice portraits with flattering compression effect while the 24-70 was used more for full length or group shots.
No one could see a 3 to 1 ratio is cost or 36 to 16 mpx ratio.
I can say without reservations, if one can't get the shots they seek with the D7000, upgrading to 24 or 36 or 48mpx is not going to fix that. Neither is 102k ISO going to make 25k of the D7000 obsolete, neither is a usable, practical setting.

What can be improved on is the video mode flexibility, AF, USB3 and the flexibility of 24mpx which allows downsampling and cropping advantages over the D7000. The AF module Multi-CAM4800 is getting strong praise in the D600 so expect some improvements from further tweaking over the D7000 by using a higher res metering sensor.
These sorts of additions will probably not warant upgrading from a practical point of view but many will upgrade simply because it is available, plus those who have been sitting out the last severall upgrades or are coming from an entry-level camera.
Stan
St Petersburg Russia

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