Indeed self driving electric cars would be a dynamic innovation of near future. But still Im quit skeptical about it. Some of the key cons I think that will effects are..

-electric energy is also among the non renewable source of energy,that may be a danger to our water bodies.

-If may take a professional drivers who can understands how to interacts with the Artificial Intelligence.well that can discharge many jobs out in future.

-batteries stores energy but if something goes wrong with it it may blast,we have seen in past with some of the leading mobile manufacturer including Samsung.

-as you say building a hi tech centralised control system is the biggest challenge of all, I say building a default mode would be the biggest challenge to get car into safe mode if AI can't be able to understand human out there.