Earlier quoted context omitted.
All I saw was an opportunity for fragmentation. If a developer wanted to make an iPhone app that took advantage of the new resolution - he'd either be limited to the original iPhone resolution, or to only the consumers that had the iP4. In either case, I can't imagine games running their own UI would look better as the images are limited to their original resolution. Only the UIBuilder interfaces will look sharper. W…
the screen doubled on the x and y - not too hard for the developers - just have 2 version of your bitmaps or scale the higher rez down.
This will work great for the web - but when initial size is a factor (along with video memory that is still shared with the OS - is there more video memory in this version?) this actually creates more of a limitation as you could reach the ceiling quicker with no more functionality - just higher res images.
So two versions isn't likely - scaling down is time consuming, battery consuming, and a waste of space. For optimum distribution, you would need a 3G version, a 4G version, possibly an iPad (HD) version, and maybe even a lite version of all three. You now have six version on the App Store.
One compromise is to make a 3G version and a 4G retina display version - of which would probably look ok on the iPad because it has 78% of the pixels.
I've developed multiple graphical applications and games for the iPhone so my perspective comes only with experience. Textures were always a hardware/memory limitation (it also only accepts textures in the size of a power of 2 - meaning you will need a sprite sheet layer as well) which made development-for-delivery a little tricky.
I didn't hear anything about more on-board memory so despite my fragmentation comment this actually doesn't help much. a 300x200 transparent PNG takes almost a meg of RAM.