People need to stop reading the crappy draft publications. that give players rankings out of 5 or 10 and put a random ceiling on them. It's free for a reason, a lot of the time sites like the hockey writers can't even get names or stats right.
Yes pettersson is a riskier pick than Glass or Vilardi, but if he fills out in size to 6'2 185 to 190. He won't bust, he is too skilled for that.
Pettersson has better hands and a better shot than Glass already and he's a lot lighter.