He only stayed in Finland 1 year after the draft. Plenty of Euro players stay there for a year or two, some longer, without apparently hurting their development. In his first 88 AHL games, over 3 seasons, he scored 48 pts. Not great, but not bad. His last session in the A was 17 gms, 6 pts. Small sample but in line with what his NHL play had become.
I think it is more likely that Jets tried to change him. I'm not sure what the plan was but it clearly didn't work.
Back in Finland he has done quite well. He is up to a ppg pace this season. So he must have some ability.