They should buy Waze - awesome social interaction and brilliant interface for reporting issues and crowdsourcing is already there with speed, etc... then put their gorgeous cartography on top of it.
For a first venture, Apple's maps is actually quite elegant in many aspects. I'm sure the next iteration will be quite an improvement.
I had my TomTom GO 2435 on my dash along side my iPhone 4S to compare the mapping. I saw no evidence of true re-routing or crowdsourcing as promised in Apple's mapping. After a month of testing them side by side, I stopped using Apple's maps.
Then, I started using Waze - and tested that side by side w/ my TomTom for a month. The Waze app won hands-down. Not 'perfect,' but close enough - and a lot more intuitive menus than TomTom.
I LOVE Waze for navigating road hazards, reporting police activity and for traffic and re-routing - beats the pants off Google & TomTom big time. Apple+Waze would be too awesome for words.