Lundell actually played 4 less games than Miller, and half of those extra points came from the PP. Their p/60 was very close. Lundell has 2 cups under his belt and has played very well in the playoffs. I'd say he has pretty good chemistry with the other players on that team. And he should only get better, while Miller, who will probably bounce back next year if fully healthy, is on the downward part of his career.
I just don't see any way to justify giving up 9 years of Lundell for Miller. If the roles were reversed, we wouldn't make that deal.