The only regret with pre-ordering a Nissan Leaf before release was that the company Nissan hired to run the pre-orders fucked it up. People who ordered up to six months after we did got their cars months before we did.
But when we were finally given a hard date, it showed up on that date, and we've been happy with it since. The only reason I don't jump in line for the ID is because my wife and I are really hoping they build that concept van to replace the '81 VW Westfalia we've got now. They announce that for pre-order, and it's "shut and take my money" time.