Here are the results:
Year ESG/60 Mins
This isn't exactly correct; I'm including OT goals but not OT time. I'm also assuming that the average length of a power-play that ends in a PPG is one minute, and that all power-play opportunities where there's no PPG are two minutes. This is not correct, but NHL TOI data is terrible before 2002-03, so I pulled this from ESPN and made the approximations. I'll take a look at the NHL data again and see if I can do a bit better.
At any rate, even-strength goal-scoring was dropping very precipitously prior to the lockout. The new rules completely changed everything - but the league has quickly come back to where it was just before the lockout. On top of that, as James' post shows, the rate at which penaties are awarded has dropped too. Everything's back to where it was in 2002-03 - but we have a lot more hooking calls. So even though scoring rates are no different, clutching-and-grabbing is much more likely to result in a penalty - which potentially allows for more skilled play, though I'm not convinced.