Not the first message here, but still having trouble to use appropriate hockey slang, so sorry about that.
Helenius played for the team that I support, and yey, we won the championship. And yes, it's the top tier. It's kinda hard to compare the Swedish, Finnish and eg. the Swiss league, but I wouldn't count only on that one swede's opinion (as it happens, our team won all the preseason games it played against the teams from KHL and the Swiss league - didn't play against any SEL (swedish) teams). KHL is the top league in Europe, that's for sure - but then... I don't know. But I would say one thing: FEL could perhaps be described as the most North-American style of hockey. Anyways, not gonna go into that now.
Helenius played reasonably well in the season, but on the other hand our team (JYP from Jyväskylä, go ahead try to pronunciate that) has been noted for the last four seasons as one of the most defense-oriented teams in the league. Well, maybe not just one of them, it is THE most d-oriented team there is in FEL. It has allowed the fewest goals in each of these four seasons - even without Riku, who came to JYP this season.
At the start of the season Riku was a bit shaky (umm... if you know what I mean?), but the d-men were giving a huge helping hand, so the stats may be a bit deceiving. BUT, on the other hand, in the playoffs he played insanely well. JYP lost three of its best d-men (due to injuries), but Helenius improved his play a lot at the same time. Loads of game savers, and I would even say - did not allow a single easy goal. He was one of the key factors for JYP winning the championship. 11 wins out of 13 games for him, not bad at all. Other stats have already been posted here before.
I'd say that he has loads of potential, but I think he's not ready for NHL yet (and yes I know he has already made his kind-of debut there already, but still). Maybe another great season for him in the FEL, and then... Who knows?