There is always new technology to squeeze out the tiny additional bit of improvement. I doubt any back lighting, it does not improve that much for large sensors, and will cost a lot more. We will see reduced circuitry size, more readout columns, gapless micro lenses, and lower noise readouts in addition to lower noise in digic V.
We would be very lucky to have all this add up to more than 1/2 to 1 stop actual sensor improvement. However, adding 1/2 - 1 stop to all my lenses might cost me North of 10K.