Meh, what's with all these predictions that upcoming iDevices will use resolutions that will further fragment the iOS ecosystem? It's fine as is, there's only a handful of different resolutions to design for... but let's not add any more.
While I agree that it´s certainly not desireable to have too many resolutions, Apple really needs to think about the future and the current resolution situation isn´t really the best base to continue.
1080p is an industry standard and it´s going to be here for years to come. With that resolution you also wouldn´t need to use scaling if you feed the display with native 1080p content. And even for other 16:9 content like 720p, there would only be minimal scaling involved, which leads to a better picture. Oh, and I didn´t even talk about downscaling. If we soon get 4K content, you would only need to reduce it to one fourth of the resolution to get 1080p. There are only positives to this and only very few negatives.
Apple should finally wipe the slate clean and go with the resolutions people actually use in their everyday life. The earlier, the better.
If they offer an iPhone 6 and they can make good improvements upon the great 5s, Apple will get my money again. But this time, I want a bit bigger screen (around 4,7" would be optimal, because that´s about the size I would consider practical for a smartphone) and hopefully 1080p.
Another important reason is that the iPad currently comes with 16:10, while the iMac already is 16:9 (if I remember right) and their Macbook Pros are 16:10. I highly doubt that Apple wants to skip 4K for future Macbook Pros or their Cinema displays so they would also adapt to an industry standard.
So in the future, 16:9 and hopefully 16:10 should be here to stay.