Let me backtrack a bit.
If we take a look at comparables in the NHL, you've got Erik Gustafsson, John Klingberg, and Erik Karlsson. All of these players have a similar style, but they vary in skill.
So imagine this is the spectrum:
Erik Gustafsson--->John Klingberg--->Erik Karlsson
Adam Boqvist could fit in anywhere along this spectrum depending on how he progresses. So if everything goes according to plan, he's EK. However as we know development isn't a linear path and things can happen along the way to deter progress. So although we'd love for everything to be perfect, that just doesn't always happen, meaning I think it's more likely that he lands in the Klingberg or even Gustafsson side of the spectrum. But as you mentioned, Karlsson probably didn't look like he'd project to be on the Karlsson end of the spectrum at the same age, so anything is possible. I just think we need to be open to the different possibilities, because he may or may not meet expectations.