I don't care about multi tasking on the iOS level. That's why I have a MBP. I am concerned about what it may do to battery life.
From a developer’s perspective, the current iPhone 5/5s/5c display has a resolution of 568 x 320, up from 480 x 320 in the original iPhone. However, there are actually twice as many pixels in each direction to create a sharper image. In other words, an iPhone 5s with a non-Retina (or “1X”) display would have an actual resolution of 568 x 320 (which is the 1136 x 640 resolution divided by 2). We’ll call this the “base resolution” of the iPhone 5/5s/5c.
3X mode:
Fast forward to 2014, and Apple is preparing to make another significant screen adjustment to the iPhone. Instead of retaining the current resolution, sources familiar with the testing of at least one next-generation iPhone model say that Apple plans to scale the next iPhone display with a pixel-tripling (3X) mode.
Don't know, Sam....I'll go on record saying I don't think you are gonna see a 5.5. The 4.7 rumor seems too prevalent with actual replacement parts leaks but the 5.5 seems like a pipe dream based on internal tests only, for this year anyway.