You answered your own question on Laf. It's a lack of speed and creating space. That extends to not only creating his own shot, but also creating space necessary to exhibit playmaking skills which were billed as elite.
He's actually quite good at being in front of the net, doing some dirty work, deflections (very good hand-eye coordination). He is one of the only guys on the team willing to forecheck and pester puck carriers, but he's not nearly as effective as he could be. His mind is in the right place, but his body is not. His frame needs to fill out more and he needs a half step or more of foot speed. These things are attainable with appropriate training.
It's not a surprise, but also worrisome, to hear his offseason training has not nearly been good enough that it's starting to leak out of the Rangers org. For a guy who I think clearly has a compete gene ON the ice, why has he not been willing to compete OFF the ice? Being a good pro hockey player is not just a 8-9 month job with summers off. It's year round, and the 3-4 months of offseason matters just as much if not more.