Hi.

Easier install doesn't only benefit the nav project, but many others as well, most notably: displayserver (at least as soon as Frank gets to adjusting it to beta7 and hijack). Also, it does make testing a bit more convenient.
As for the graphics (or general UI) API: hijack only provides a nice way to overlay the content of a buffer with the current player display, but no convenient way to fill that buffer or to generate and handle the menu structure of an application.
I intended to create (and started working on) an API that handles the menu structure, allows easy image display and basic drawing instructions like lines, circles, arcs and stuff like that.
Regarding PDA support: I do not intend to directly support it, but I want the API to be abstract enough to allow easy porting.

If you want basic GPS data display, just start and write such an app. Noone is gonna stop you (to the contrary, many will support you).

cu,
sven