Tesla has made an electric vehicle that doesn't make anyone with a sense of style want to puke, and that's a very good thing, but there's just a handful of things they need to do, IMO, to really knock the ball out of the park for electric cars:
1) One needs to be able to charge it quickly, perhaps with an upper limit of about 10 minutes or so, sufficiently to go approximately as far as one could expect go on a tank of gas in a typical car of today. I would not expect to be able to charge it this quickly on conventional house current... it probably would require a dedicated type of charging circuit. But this would make recharging a car at such places not significantly more time consuming than filling up a car with gas, and would make owning an electric vehicle vastly more convenient than it currently is.
2) Charging infrastructure needs to be ubquitous, so that if you can drive there in a regular vehicle, you should be able to get there and back in your electric car as well.
3) The pricing structure for an electric car should be comparable to that of an otherwise similarly equipped gas-powered vehicle... and should not carry a premium cost that is almost equivalent to buying an additional automobile. Making them affordable, in addition to the other two points, will mean that there's no reason for people not to drive one.
If or when Tesla, or any electric vehicle manufacturer, can hit all three of the above points, I'd dare say that the writing will finally be on the wall for the age of gasoline, and I think electric cars could outnumber gasoline vehicles on the road within a decade.