I'm not too worried about the sprint speed as even that is a bit flukey in a small sample, although I do agree that it's something to monitor, and weird given the lack of (known) leg injuries.
As for the offense, he's trying out a new swing this year and is probably still in that adjustment period with it. Personally, I prefer the old version of him (40 bombs + respectable OBPs) to this new version with less power and more walks, but obviously it's early and I'm sure things will change. He's also hitting a bit better as of late. The concerns are valid but he's the kind of guy I'd feel confident rolling the dice on. When he gets hot, he carries the whole team