I'm 90% sure Hank's stats have actually gotten better after recent size reductions, but ok.
This is nothing but my own opinion, but I would not be surprised to see that turn out to be completely untrue.
Penalties and coaching systems would have a much larger impact IMO. I mean, the last time they shortened goalie pads was a couple years ago, no? Scoring has stayed exactly the same.
The thing about this, is that even with "reductions", the massive overages of pad sizes are still allowed. Sizing something down from "ridiculously oversized" to "only a little bit oversized" as has been done...really doesn't change things that massively. Some goaltenders were actually permitted
larger pads than they were using before in the change of sizing rules.
"Thigh Rise" wasn't a "protection issue" until the modern pro-fly goaltending style became a mainstay of the NHL. Even with the pioneer champion of the modern butterfly style Patrick Roy...the thigh rise was...a reasonable and justifiable amount for "protection" and was functionally very different as to how the pads operated. Something that is ignored in this whole thing a lot, is pad rotation...which has become a major point of technique in the modern era. And further contributed to the idea of basically..."A Wall of Pads" that takes away the entire lower section of the net, 11" high from side to side.
At the end of the day...you've got goaltenders under the rules, with a pair of goal pads that total the entire width of a regulation NHL net @ 6ft, designed to rotate flat on the ice independent of leg rotation, @ 11" of height.
You've got goaltenders who, even if they weren't to play the position at all, and were to just hang out on the goal line stretching their pads from post to post...would essentially take away some ~12% of the entire scoring area of the net...without even having a goaltender attached to those leg pads. And it's not as though the other equipment attached to a goaltender is small, or reasonably sized.
That is absolutely a plague on goal-scoring ability. You start at a basis of 12% of the net gone, the further you telescope that out, the higher the percentage becomes just from those two leg pads alone. Relative to a shooter...there's a point at which just the two leg pads alone constitute a 100% save percentage based on trigonometry and whatnot. And that's a HUGE component in decreased scoring in the NHL...without a shadow of a doubt.