He stopped using the first version because of EC3 in TNA I think, whose been using the move longer. That said, I do like the fact that a DDT is a finisher again. It's been a long time coming as far as I'm concerned.
Overall, I agree about Ambrose. He's never excited me, even when he was on the indies. Good for him though on achieving all of his success though. It seems like WWE is behind him because he has that "CM Punk" type of aura about him.
Honestly I think a tornado DDT or even a standard DDT looks more impressive than that one, people have the option to flip over with those two versions of the move but his makes them look really protected.