Just a followup on my previous post, my Flex app gets 58 fps on the iPad 2 while a user rapidly scrolls a TileList. On the new iPad with retina compiled against the ios 5.1sdk, it gets 22. So I'm betting AIR apps that could compete with native apps with a non-retina display are going to have a new mountain to climb. It will be interesting to watch when Adobe releases retina updates for their own AIR apps, such as Photoshop Touch.
I'm not seeing much in the way of a bump on the CPU at all from ipad2. Perhaps ~5% using CPU blitting. Pretty terrible being it's a landslides worth of difference between iPad1 and iPad2.
I haven't touched a single thing in my apps and the embedded font outlines are rendering much better. Although to tolerate iPad1 I had to set stage quality to low (using mostly bitmaps anyhow). My app looks pretty much identical in iPad2 and 3 side by side, except fonts are smoother on iPad3. Also, obviously, StageWebView content is much sharper.