For the most part, 99% of what is done on the iPad is 2D drawing, which requires a linear increase in performance. 3D on the other hand is geometric as each pixel is rendered over several times before getting the final picture. I predict we'll see 3D games like Infinity Blade 2 continue to run at 1024x768 and use anti-aliasing to cover up any imperfections.
Anti-aliasing on an iPad 2 calculates color values at 1024x768 resolution, but the geometry at double resolution 2048x1536, and then shrinks the double resolution image down to normal resolution. On an iPad with double resolution, you can just drop the step where the image is shrunk, and get a slightly better image (sharper where edges of different objects meet) at slightly less cost.
And for games it's not a problem because they can run at 1024x768 as before and just be upsized. They only would be a bit pixelated but that doesn't matter much.
Slightly better than on 1024x768 actually. It would only look pixelated if Apple built a 20 inch iPad.