I just watched a bunch of his footage and I don’t get the Boeser comparison. Boeser is more of a soft area, quick one-touch shooter who isn’t very mobile.
JL seemed much more comfortable moving around the ice and he was comfortable holding the puck and finding the right shot or pass (but I do agree he did sometimes miss the better pass options for a worse one or elect to shoot when he could have had passed). I see more of a Pastrnak to his game if anything the way he moves, shoots, and processes the game. I get the excitement about him from some scouts and the Canucks; if he’s anything close to a smaller Pastrnak-lite he can be a very good player.
I think he's a bit more of a cerebral sniper than Boeser is. He plays a lot of mindgames with the puck on his stick, while Boeser's scouting report from when he was drafted thats somewhat carried into his play in the NHL is being a sturdy, fundamentally sound shooter.
Boeser is the more strong forward that leverages accuracy and his quick release to put the puck where he wants it, while Lekkerimaki is a bit slighter, relying on skill and deception to make his openings. His release is pretty interesting and atypical; he rushes through his shot while limiting his follow-through for a really snappy and hard to read wrister. It doesn't give the goalie much time to read his shoulders and hips, and he requires very little setting and leaning to begin with because of how adept he is at using his stick.
As we've seen with EP using his slight frame to blast 100mph slapshots and top shelf wristers off the rush, stick technology has gotten to the point that using your stick more than your body to give fewer tells while not sacrificing power has become an extremely viable and dangerous weapon. Moreover, needing less time and space to let off quick, accurate shots means a lot more high danger scoring opportunities from more areas of the ice. I've heard him described as "always dangerous", forcing respect from defenders and preparation from the goalie at all times, and his shot is a huge part of why.
I'd say the differences in Boeser/Lekkerimaki come from their frame, and how they influenced the development of their skills and playstyle in junior. Boeser is, and projected to be, the better two-way possession player due to his strength and center of gravity, while Lekkerimaki is much more in the mould of Pettersson or Pastrnak that developed their scoring instincts while being smaller and lighter.
For reference, when drafted:
Brock Boeser: 6'1 192 lb
Elias Pettersson: 6'2 161 lb
David Pastrnak: 6'0 165 lb
Jonathan Lekkerimaki: 5'11 172 lb