I don’t know if I agree that he overcommitted to the man in the slot or that that constituted not being in position.
I believe his job as the weak side D, he is the #1 person in charge of the net front. That is his main job, and he follows his man well.
The puck gets passed to his side and now as the strong side D he is responsible for fronting the shot. If the puck had to go around the perimeter to change sides, he would have had time to set up - that, I believe, is one of the central aims of the PK. Prevent seam passes because seam passes are DIFFICULT to cover.
In my opinion that was a difficult spot to be in and failing to get in the blocking lane is understandable.
In the offensive zone, generally I agree with you he is very safe on backing off for fear of being beaten by speed and that is a downside of having a slow defender.
That being said, it isn’t all bad. I personally remember some good keeps, some good aggressive plays at the line. Saying “he doesn’t ever save a play at the line” doesn’t ring true to me.