DanielBrassard
It's all so tiresome
Yea I wrote up a whole response and then deleted it. But essentially it's not even a baseball comparison. It's a numerical comparison and I just used baseball as a tool because it has stats that are simple enough and do a good job at what we're trying to approximate. Obviously hockey stats aren't nearly far enough along to do anything like that but the same point still stands. It's the exact same thing for hockey as baseball. Girardi is worth some value X. Letang is worth some value Y. If they both played in the same amount of games I think we can all agree that Y >>> X. Letang is so much better that even by playing some decent percentage of games less he still likely provides more value. These curves are very right skew. There's a ton of players close together around and slightly above the zero point and then very very few as you reach far out where is closer to where Letang would be.
I have to say though a defensemans role isn't to "play defense." It's the same as every other player which is to do things that will provide the largest differential possible between GF and GA. That includes defense, offense, and all sorts of things. Nobody thinks Erik Karlsson at "defense" but he's still one of the best defenseman because of how great he is at doing other things. There's no effective difference between a player who say has true talent 4 GF/60, 3 GA/60 and a player who is 2 GF/60, 1 GA/60 except the first player is higher variance. In terms of expected value they are the same.
I didnt see the 2nd part of this post last night but this is pretty much the crux of the issue. Great point.