Calling the EV1 a failure is a bit problematic. At the end of the day the vehicle wasn't available in any numbers and was then forcibly withdrawn from the customers who did want it. Add to that pretty decent documentation of dealers actively pushing customers away and the whole insistence that no vehicle be left operable in so much as a museum and the EV1 looks a lot more like something the company wanted to go away without a proper test than a failure as such.
As for CitiCar, you mainly need to get better speed and more range, though yes, a more appealing vehicle can't hurt. At the end of the day this is the kind of vehicle that did more harm than good, having the performance of a souped up golf cart rather than a realistically usable car. In the real world people are concerned about range on a vehicle that does one or two hundred miles, something that does forty doesn't even meet the needs of some pretty typical commutes.
So, as ever, it comes down to batteries. You need something a lot more like the EV1 than the CitiCar to be more than a curiosity in cities that look anything like ours do. Yes, there may be a niche for so called neighbourhood electric vehicle, but I honestly don't see any way to grow that sort of business into producing real cars as there just isn't much technical commonality between what is in essence a golf cart and traditional cars that are, ultimately, designed around highway operation. For that matter I fail to see many purposes that a "neighbourhood electric" is suited for that a traditional golf cart couldn't fill significantly cheaper.