I honestly thought that guy was a troll when I first read that SA thread. That's probably just my paranoia from years of forum whoring, but I don't think I could do a better job at trolling the DF community than posting a video of nothing but a UI and then start making comments like 'when I do my game, I'll do this and that properly' (I mean, without obviously being a troll, like posting a video of nothing but a UI then stating your game is already better than DF).
Or he could be trolling the SA community, by posting a video of nothing but a UI that they all get excited about despite knowing next to nothing about the gameplay. Meh.
Assuming he isn't a troll, this is still nothing to get worked up about. I'd love to see some DF clones (for purely selfish reasons, nothing pretentious like 'competition for Toady', I'd just like more games to play). I doubt this guy is going to be the answer. Programming a game like DF (or indeed any decent roguelike game with a single programmer) takes many years. You don't need to be a hotshot programmer to make DF, you just need patience.
This guy has what appears to be a half-finished 7DRL that he already couldn't wait to show off. That doesn't smack of patience to me. Maybe he'll prove me wrong in a few years time (I wouldn't mind be proven wrong if it means a free game!), but I've got about a half-dozen abandoned projects sitting on my pendrive right now that are about as impressive as Goblin Camp.