Another key factor is Zetterberg making Toews irrelevant at best, and possibly a liability. You could see how frustrated Toews was in game 4, but it's been going on the entire series. Same game plan as in '09 when Z shut down Crosby.
The rookie line (especially Nyquist) is really stepping it up in the playoffs as well.
I would have to say the three stars of the series so far are:
1) Howard
2) Z
3) the posts