Walker has been quietly solid this year. Unlike in years past where he would come in with a ton of energy and jam, moving play in the right direction for 2-3 games before falling off, he has surprisingly kept up a steady level of play over a longer stretch then he was previously capable. He's producing well above a 4th line level on his per/60 metrics. I don't think he should be given a bigger role, but Walker has been an above average 4th liner this season.
Peru is fine. I really don't understand the frustration people have with him. What were people's expectations going into this year? He had all of 25 total NHL games and that was two seasons ago. Has he been sheltered? Yes. But he's also produced fairly well in his role.
At 5v5 he's the top D in terms of Corsi and Fenwick percentage, and he's right below Krug and Faulk (6th best on the team) in xGF%. He's producing the most assists/60 of all our D-core, and he's MILES ahead of anyone on primary assists/60 of our D-core. He has a positive GF/GA differential at 5v5 of +1 and is even overall on the year. Peru is currently making league minimum against the cap.
On the PP, Peru has about 100 minutes, same as Faulk. Krug has double. Peru has as many primary assists in that 100 minutes as Krug has in 200, at 3. Krug has more secondary assists at 7 to Peru's 3. Neither of them has scored a PP goal all year (In fact, the only D-man with a PP goal at all is Faulk, at 1. This is a big reason why our PP sucks, b/c no one on the point is a threat to score). Again, Peru is currently making league minimum against the cap.