For me, it's global shutter CMOS sensors in consumer DSLRs.
it's a big topic
I hope they won't increase but decrease number of megapixels, which in turn will:
- require less expensive glass
- slower or more efficient CPUs
- better battery life
- global shutter will be achievable
- faster sensor readout and
- less rolling shutter in video
- better low light performance
- better color performance
- no overheat or time limit for video
- cheaper overall camera, CPU, sensor, lenses
- With big pixels even Foveon might become feasible.
Other things
- webcam function
- get bigger batteries and better grips for mirrorless
- start selling cheap prime lenses
- offer decent zoom lenses, not soapy muddy ones
- try matrixes other than RGBG. that will improve demosaicing performance