Besides Perron, Arcobello, Gordon and Bryzgalov, I'd say that no one has played up to potential. He is playing well defensively but he needs to get stronger to take his game to the next level.
RNH is a black hole defensively this year. Missed assignments, weak on pucks and awful exiting the zone. It's not about him getting stronger. It's about him not being content to skate around the edges of the rink and trying to feather wrist shots through 4 players from the half boards on the powerplay. Take the puck into traffic and get your nose dirty.
For all the crap Eberle takes around here, he, Perron and Hall at least all go to the center of the ice to try and get scoring chances. RNH is content to just circle back to the boards to try and look for that sweet pass time and time again. Every once in awhile he'll sneak one through. It almost never works. Being stronger isn't going to make him play less like a puss.
The only thing he did positively last night was keeping that puck in in the dying seconds and throwing it on the net. That was a heads up play not to look for the silly cross ice pass..