Another vote here for keeping the D7000.
I'm in the same boat - I could upgrade, but why? I see no need. The big upgrade for me came when I bought the D7000, which compared to my older camera (D80) offers a bunch of new features that I really use and rely on a lot. User-customizeable presets, front and rear IR receivers, much better high-ISO performance, MUCH much better long-exposure low-noise performance, larger buffer size, faster "motor drive", built-in level (in the monitor or on screen) and even live view (which I never even considering needing until I found a few situations where I do use and rely on it). Any improvements beyond these would be incremental and probably not worth the expense.
I have a FF D750 too so my needs are satisfied for the forseeable future, both full frame and DX.
Nikon S2, S3, F, F2, F3, FM2, FA, N90S, D80, D7000, D750, Sony a6000, Canon IIf, Leica CL, Tower type 3, Zorki 4, Vito B, Perkeo II, Rollei 35....