Our PP is an issue and it's been a disaster in the playoffs for the last number of seasons (so has the PK). And nobody bring up the regular season stats trying to say it's good. It's a powerplay where elite skill is able to override the ineptness of how ot runs - and when the intensity cranks up a level in the playoffs it gets exposed.
But Rielly is not the problem at all. The best evidence is the fact he's been taken off it multiple times and whenever that happens the PP gets notably worse:
Barrie - big point shot, QB on effective Avs PP for years, now QB on the top unit in the NHL. Complete disaster on the Leafs PP.
Sandin - bigish shot, crafty passer, replaced Rielly end of the North Division season and start of the playoffs and the PP put up a mind boggling 1 Goal For and 2 short handed goals against with Sandin running the 1st unit.
The issue is simple, everything is too slow. Every player on it wants to handle the puck whenever they get a touch, every pass is soft as butter and the main puck controller always wants to make one 'extra' pass or move or whatever. The PK has so much time to get in position and pressure the puck.
My girlfriend is an Avs fan and watching their PP run vs ours is like night and day. The passes are hard, the decisions are quick with one touch passes and one time shots.