I think it make more sense to build the UI with (most of) the buttons and overlays at the bottom of the screen. If you are tracking your position, then the map is always oriented with where you are headed at the top of the screen. That is where the on-screen zoom buttons are located and they obscure your view of nearby upcoming roads. In contrast, if those buttons were located near the bottom, the portion of the map they obscure would be behind you (which seems to be less important than where you are going).

I know you can hide the zoom buttons and bring them up by touching the screen but that simply requires one more touch to accomplish the task.

I should mention that the location of the top status bar is fine.

Ken