I suspect the chips will be cheaper as a result of newer silicon fabrication techniques. Just as with computers where similar technology cost less over time.
The HD2 chip is still 1280x720 resolution. The performance benefit is supposed to be from the micromirrors tilting to 12 degrees rather than 8/9? degrees. Also the chip is supposed to have a black, light absorbant coating (this might be for later though, I got a bit confused keeping track on AVS). Together with better bulb tech expect to see brighter projectors with better contrast ratios for less money. (very big hopefully here).
Sounds good generally. Still no chance of me having any cash to buy one though