Higher resolution? Real growth would be driven by increased supply of 4:3 panels
What the world is really waiting for is an increased supply of 4:3 panels and the existing resolution will do just fine thanks. Asus have admitted privately that they won't ship a tablet in the same format as the iPad because Apple is using most of the available supply of 4:3 panels. Viewsonic do have the VIewpad 10e, but that's because they make their own panels. Unfortunately they have aimed the 10e at the bottom of the market, either because they are afraid of lawsuits from Apple, or because they have misread where the demand lies.
I can't see higher resolution screens driving much growth (although there will be growth anyway), I suspect most of the initial buyers will be people who already own an iPad 2 and further sales will be to people who buy for reasons other than the screen resolution. How about a tablet aimed specifically at digital camera owners with a full size SD slot and that could double as a digital photo frame - now that really would grow the market.