BlackBerry Maps, which is the software RIM releases with their GPS hardware, will not have turn-by-turn directions. You would need to go with software from Garmin or TeleNav for this functionality. I think your ideas behind GPS are a bit confused... the GPS chipset companies and even the mapping data companies provide the tools necessary for software companies to do what they need, whether it be multi-destination, turn-by-turn voice navigation, etc.
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.