What makes you think he'll score more when he's matching up against opponents' shutdown lines? I'm not saying he can't produce at a higher clip, but I do think there's too many excuses flying around right now as to why he didn't put up more points. It might also be the other way around. It's not because he's given the defensive zone responsibilities that he doesn't score as much, it's because in practice and in games he hasn't shown he has the offensive abilities that would put have him in a more offensive role. His minutes don't seem suffocating to me, either.
I do like his role, though, and am perfectly happy having him play it for the rest of his career. He's good at what he does and I'm not expecting him to turn into an offensive juggernaut. But, again, that's fine with me. If he does, however, all the better.