I don't see the Johnsson comp - Johnsson's big weapons are his shot and speed, scores off the rush a lot and his cycle goals usually come on either backdoor feeds or high slot shots through traffic...maybe like a poor man's miniaturized Alex Semin is a good projection
Grundstrom seems to almost exclusively score from below the faceoff dots. Some of his D+1 goals have shown more talent than the pre-draft ones, but still mostly ugly goals from what I've seen. I think Tomas Holmstrom looks like a good comparison for his upside. He's not as sexy of a prospect, but I think that could be very useful in our ultra-skilled wing prospect corps