It turns out, they do go up - every year post-lockout, there are more power plays per game per team in the first round than in the regular season:
|Year||PP/G Reg||PP/G Plyff||Difference|
The difference hasn't been enormous, but it's there. I suspect it's a combination of the factors I mentioned above - players going at full speed every play, every board battle becoming incredibly important, and referees feeling the pressure of more eyes on them. One hopes that the referees do not decide to call the interference penalties they've been not calling for months now - not that I enjoy the slower game, but I don't like it when players don't seem to have any idea what is or is not a penalty.