Things I'd like to see and that I think only make sense to add (eventually) in no particular order ...
(a) More pixels (duh).
(b) Less noise per pixel.
(c) Better quantum efficiency.
(d) Larger, 32-bit, dynamic range options.
(e) Faster and longer duration fps, which will be a consequence of a larger on-camera memory buffer, faster processors, and faster memory (the faster memory already exists, but the camera components can't keep up).
(f) Better build construction even at the lower end.
(g) Full-frame sensors at the low-end.
(h) Introduction of (cheaper) medium-format-like digital cameras, though this may be a non-issue as the pixel number increases and noise decreases.
(i) Better battery technology for longer life and less of a capacity problem at cold temperatures.