Not sure why there are many sweeps in the first round... its not even always the best team.... I guess its just momentum.
		
		
	 
Baseball is like that. Even with the lack of parity, most games are just a crap shoot. Over 162 games the better teams come out on top, but all of the playoff teams had multi-game slumps during the season. And statistically, the idea that some teams/players are better "in the clutch" (i.e. playoffs) than others, while other teams "choke" is mostly bunk - any apparent difference between regular season performance is easily explained by the small sample size. 
Unlike hockey where teams and players pick up the intensity in the playoffs to a level that could not be sustained over 82 games - and games can be decided by grit, hustle and determination, baseball is pretty much the same during the season, in a pennant race or in the playoffs. The only real difference is that in the playoffs one is less concerned with burning out one's top pitchers, and no one is concerned with developing young players. So take any random 3-5 game stretch from the Yankees' schedule and that will give you an idea of how well you can expect them to play - the odds are that the Yankees will win, but it will be no surprise if they lose or are even swept.