There is a "fluke" winner every other year in my mind, St.Louis being the most recent. Kinda miss the pre-cap dynasties in that regard since it was actually interesting storylines, "rise and fall of empires" if you will.
Of course it's debatable if it's actually a "fluke", I think it's moreso that the margins between great and good teams are very slim and depending on some things like injuries, daily form, confidence etc any team in the league can win a best of and if they do they might gain momentum.
But let's just say they wouldn't have been in my top 5 pre season, then again neither would St.Louis or arguably the Caps(mostly due to prior track record) but it's hardly surprising either way.