BMW Nav systems

[super7]

From the very first Idrive BMW have been universally slammed for the systems lack of user friendliness.
My 2007 7 series (my 13th BMW) has one of the worst Nav systems ever. What good is a system that at large zoom in scales shows no street names or a few letters of a name sliding out the edge of the screen?
BMW blame the mapping suppliers so I contacted both Navteq and the new supplier who both say they supply the maps with all the information but Munich decide what information to put on the screen.
Paying $199 every year for the same limited info isn't very clever!
Does anyone know of an aftermarket upgrade to the standard system or a way to replace the nav feed to the standard screen more informative without making the other information one can select on the screen unavailable?

[Sticky]

You can replace the nav feed but would require a new NAV system and it wouldn't interact with your steering wheel or idrive buttons I would think.