I've been advocating for him in the prospect vote, so I'd be happy to share my opinions having watched him 4-5x. First off, Alex Nunn (AJ Ranger) put together a good highlight video of him here:
They also did a segment on him on MSG here:
Just for background, we drafted him in the 4th round 4 years ago. He had been considered a big time prospect (he was compared to Juolevi, who went 5th overall) but dropped after getting injured his pre-draft year and missing most of the season. The next two seasons he bounced around between TPS, TPS's U20 team, and 2 different Mestis (Finnish 2nd league) teams without really sticking anywhere before he got traded to Lukko last year.
Once he got a consistent role with Lukko, he settled in and produced what I think was one of the most impressive seasons by a prospect of ours last year. From December on, he became a top pairing D on Lukko, a playoff Liiga team, and scored 0.6 ppg, which is the same as Esa Lindell and behind only Miro Heiskanen and Sami Vatanen in the last 10 years. All those guys turned into top 4 defensemen on cup contenders in the NHL. Then Reunanen took his play to another level in the playoffs, scoring almost a ppg and leading the entire league with 6 shots per game.
He's a really good skater. He's above-average in a straight line but where he excels is being sudden on his edges and losing defenders with sharp turns. I would agree with this characterization:
Here are a couple examples of what I mean:
Jokke Nevalainen on Twitter
Jokke Nevalainen on Twitter
Jokke Nevalainen on Twitter
He's also a very good passer. He's good at drawing defenders to him and then making tape to tape passes to open players and he can anticipate where players will become open. The assist above is obviously a ridiculous pass and this clip below is another example.
Finnish Jr Hockey on Twitter
He'll also skate the puck deep and find open forwards in front of the net and he's very good at moving the puck out of the defensive zone. He reminds me of DeAngelo in that basically every time he gets the puck on his stick in the defensive zone he ends up making a tape to tape pass to an open player leading to a controlled exit, even when he's under heavy pressure (Drury made the same comparison).
Finally, he has a cannon of a shot. He was the triggerman on Lukko's power play and generated a ton of points off of his shot:
Alex Nunn on Twitter
Alex Nunn on Twitter
He can walk the line and read screens too:
Alex Nunn on Twitter
Jokke Nevalainen on Twitter
Defensively he plays a style where he keeps a really tight, aggressive gap and closes aggressively on forwards trying to enter the zone or steps up and breaks up passes to enter the zone. From what I've seen, he's very effective at it. Opposing teams had a really tough time gaining the zone against him and if they dumped it in, he was great at skating back to retrieve it and making clean outlet passes with control. Furthermore, I can't recall watching him get beaten cleanly on an entry leading to a high grade scoring chance. I would bet his neutral zone / transition defense stats are really, really good. He's the kind of defenseman who, when he's at his best, doesn't give up scoring chances because his team always has the puck.
His biggest weakness, in my opinion, is his physical strength in the defensive zone. Specifically, he has a hard time clearing the front of the crease, he can get muscled off the puck in board battles, and I remember one example where Palve (who was of the best players in Liiga) was able to lean on Reunanen and muscle past him for a high end scoring chance. Still, I think it's an issue Reunanen will grow out of. Firstly, he's a 21 year old playing against men, so it's kind of expected he'd be at a disadvantage strengthwise. Secondly, he's 6', so it's not like he's undersized. Finally, his compete level is really high. He regularly started scrums in front of the net because he wouldn't stop going at forwards and he's very aggressive challenging for loose pucks.
Secondly, for as talented as he is, I think he could be more assertive in driving the offense. It's not that he's bad at it, but at times he seems content to move the puck up the ice and stay back on defense or to stand on the blue line and wait for a puck to shoot. When he pushes the pace and attacks the offense, he's really good at creating offense, as you can see above, and I think there's room for him to do more of it. He demonstrated that he can take his game to another level in the playoffs this year.
In my naive opinion, I think he's got the offensive potential to play on an NHL power play and the defensive potential to play in a contender's top 4 if he gets stronger. Given that he's already a top pairing pro defenseman at 21 and everyone his age who's performed like he has in the Liiga in recent history has made the NHL, I think there's a pretty good chance that he becomes at least a decent player. Furthermore, I'm big on prospects who improve at a high rate because I think it's reflective of good work ethic and practice habits that will lead to continued improvement and he's been our fastest rising prospect. Personally, I think he's our best prospect once you get past the first rounders, Fox, Shestyorkin, and Georgiev.