I don't think it's a fluke. The Bruins were the clear favorites and legit contenders coming into the season and the rest of the teams looked pretty solid, with Montreal looking to be in the worst shape. The Sabres, Leafs, and Sens all looked like they could be playoff teams and right now two of those teams are playing to the higher end of their expectations; Buffalo's playing to the low end.
The Canadiens are, at least where I was concerned, playing above their expectations. Markov being back is a game changer and several young guys have stepped in and stepped up, so I'm not too surprised there.
I think the play from these teams is sustainable individually, but common sense dictates that at least one of them is going to slip a lot. It's hard to imagine the Sens riding high for the whole season with both Spezza AND Karlsson gone. Losing Karlsson is like the Canadiens not having Markov, but even worse.
As a side note, you misspelled dominance and I only point that out in case you want to edit it, because people like to be ****** about spelling on the internet and someone's sure to be one here.