Unless it is a problem with his feet or back, first-step issues are something that a power-skating coach can fix 95% of the time. He's never going to be Pavel Bure, but he should be fine.
They key thing going forwards will be if he can iron out those little mistakes in his game. He has that looseness with his game that partly makes him so explosive, but also makes him a target. It is a same with a lot of rookies, of course.
I am also interested in seeing how he is directed by DeBoer. T-Mac's philosophy seemed to be that every forward should be more-than-competent defensively, with a lot of emphasis on defensive reliability. I largely supported that view in the past, but I think other cases around the league have shown that such rigidity in thinking can undermine otherwise useful players. Hertl has enough creativity offensively, that giving him some rope might be worthwhile.
I can see a lot of the benefits of putting him at center. But, on the flip side, if you want to give him some more license offensively, he might be better served on the wing. Moreover, I really want the Sharks to have some speed down the middle. Thornton-Couture-Hertl-Smith isn't really a recipe for that. Tierney isn't exactly Mike Gartner, but it would be a start. Ideally, O'Regan/Chartier are firmly kept at the center position.