I was thinking about this a little last night while watching the Rangers-Blue Jackets game and they were talking about how Kent Johnson worked really hard over the summer to improve his skating and speed. I would say it's quite noticeable, and the results speak for themselves (26 points in 32 games in his age-22 season after just 16 in 42 last year and time spent in the minors to start that, his 2nd full NHL season).
Certainly a different style player compared to Smith in some ways, but just looking up what people were saying about him a year ago, I found this from Corey Pronman: "He is not without his warts, though. Johnson lacks ideal quickness. He's not very physical and his overall effort can be inconsistent."
#5 overall pick compared to Smith at #4, both college kids, so I would say expectations for the two probably shouldn't be that different. Is it going to take Smith until he's 22 to make a jump like Johnson has? It wouldn't surprise me. But my goodness are some people not going to be able to handle it if that's the case.