Not quite true when it comes to Liiga though.. Most guys who make it to the NHL manage to score a ton of points as 18 yr olds, and really take a leader role on the team. Some guys do it as 17 yr olds already. Most of the time coaches aren't hesitant to play the kids a lot because almost no one have a stacked top 6 and teams tend to be filled more with grinder types, so if you have the talent level to stand out, there's absolutely no reason not to play you a lot.
I haven't seen Vesalainen play though, and don't put any stock into stat-watching his start so far. However what im getting at is if at the end of the year we look at him and say he didn't have a good season, that will be a big red flag at least for me. Especially at that size in a league that's much less physically demanding than the NHL, you have to be able to make a big difference.
I'd really like to see him go to NA as fast as possible. Playing in Finland doesn't do much at all for power forwards and we've seen this in the past, and we end up with guys who have the frame but end up not using it nearly enough. In his case i feel like playing in the AHL would be much more beneficial,