To be effective playing his style, he needs puck reflexes like Lidstrom who could bat the puck out of the air when opponents try saucer passes. He's in the right spots to block passes in most cases, but he can't get his stick on the puck sometimes.
Here's an example in a recent game. Bert is clearly Ghost's man to cover, Bert goes in front of the net. Ghost doesn't take the body, winds up behind Bert, tries to hook the blade of Bert's stick instead of lifting it. Even despite his poor positioning, if he had lifted Bert's stick, that's not a goal. Like you said, he'd need 15 more pounds to try to outmuscle Bert with a stick from behind or push him out of the play.
2:30 into the video, Toronto's first goal:
Recap: Maple Leafs at Red Wings 11.17.23
www.nhl.com
But to be fair, his offensive contributions out weigh his defensive deficiencies. He's -3 ES, but has 10 pts on the PP, one more than Seider. The coach has LHD or RHD option on the PP, which is always nice to have.