It’s pretty clear to me that PP1 played so much for two reasons:
1. They were good. Simple.
2. The stars demanded it and both didn’t respect the coach or the kids/2nd unit. The inmates were running the asylum, they decided that they were playing the entirety of most PPs.
I have no problem with the PP1 getting lots of usage, even them starting after drawing the penalty. It’s the fact that they played the entire two minutes, or at least most of the actual valuable portion of the two minutes far too often.
I posted these stats earlier in the year. It's simply not true that the Rangers PP1 played a significantly higher percentage than PP1s around the league. They were above average but by no means wildly above average. Many teams do it. Just you don't notice it because you don't watch them for 82 games.
Of the 31 teams the Rangers ranked 8th in the league at 67.1% of their PP time belonging to PP1. The league median was 63.9% and 9 teams were between 64 and 70%. They had 278 PP mins so the difference between their usage and league median usage comes out to a total of 9 minutes on the season.
Their usage was basically in line with most teams that do not run split units. The true extremes are Edmonton (87%), Florida (76%), Vancouver (76%), Washington (74%) on the high end and then Detroit (53%), Arizona (53%), Philadelphia (53%), Montreal (53%), and Anaheim (51%) on the low end.]
Their is also a pretty direct correlation between PP1 TOI % and PP%. In fact of the 11 teams with PP1 usage below 60% Arizona is the only one who had an above average PP% on the year. Conversely every single team above 65% (13 teams) with the exception of Vancouver had an above average PP% on the year (and Toronto who was dead average).
I would honestly not play the PP2 ever unless the game is out of hand (in either direction), the PP1 players were just on the ice and need a breather, or it's a 4+ min powerplay. That is, of course, not to say you can't mix up the personnel of who is on PP1 at times or even within a game.