Smith has played well so far and I'm curious how it goes as that team develops, but I've never said Smith was a bad skater. He's a good skater that is average/above average at the NHL level when adjusted for size. The production and good at everything, great at nothing is where my concern lies for him. Right now he is keyed in on the prime offensive minutes for New Jersey on a team that is lacking overall. That can inflate stats sometimes. You don't even have to leave that same team... Will Butcher popped onto the scene with some huge numbers the first part of his rookie season and ended up with 44 overall that year. He's been in decline ever since. Now Smith is a lot better than Butcher ever was and he's going to be a good defensemen, it is just about levels.
Carrying the puck doesn't mean he relies on skating. Rantanen's game has a lot of carrying the puck in it, and he's a bad skater. Timmins isn't about skating away and creating space that way, his hands are how he creates space with the puck and he looks fine in that area. The game is a bit fast for him right now, and he isn't strong enough yet... but what really matters in his game isn't showing a large flaw at this point. It could pop in as teams get tape and target him in different ways, but right now I don't see a large concern.