You're certainly right about its CPU being very slow, but still, all other apps that use Apple's UIKit (standard visual elements, like menu bars, sliders, buttons, etc. - it doesn't matter if they're "stock", or are heavily modified/themed) are just as fast as they are on iPhone 5 or iPad 4.

GMaps uses something else for the UI (the "slide from side" thing) and that's the problem.

Still, I'm not really complaining. As a developer I know it's hard to write something that both pleases you aesthetically, and is performant on all devices!