Kakko and the other kids work out very hard during the summer months. Hard work and dedication is not the issue. He is following a scientific plyometric training program, with outdoors training, gymwork, ice time, skating lessons, and other sports like badminton/floor ball etc for "off days". And he is building on the NYR's wish to add more "skating and power". The Rangers themselves bulked him up this spring and I'm pretty sure they worked on his skating towards a more power stride. To me the question is more is his current training tailor fit for his current needs and what is the NYR's vision for him? I ask that as most of us see his biggest immediate need as burst speed. But the Rangers want power for physicality so power it is. The Rangers are also asking him to be Jesper Fast right NOW while also wanting him to score more...
Look at Kreider, physical specimen that he is. Kreider is very fast, but he also has a turning radius of 2-3 meters, he is not that nimble on his feet. Kakko's offensive game was always about nimbleness and elusiveness. I feel the Rangers idea/stereotype/vision of how to develop Kakko does not really meet who he is and I've felt that from the very start. And that goes back to what Amazing Kreiderman and many others here have pointed at, the Rangers are cooperate and aloof in their approach rather than meet individuals at where they are and who they are. Toronto, and now Montreal under Gorton's new vision and other clubs (Vancouver etc) are attempting to move away from this old fashioned approach.
Personally I'd model Kakko's training on how (eg) Kaprizov with his agility moves around the ice in the o-zone. Core strength, butt/leg strength, lots and lots of jumps and burst speed/foot speed training this summer is the ticket. Spend the skating lessons primarily on the five first step burst and how to use the hips for power/speed tailored to his personal body build. LOFIN, me and other Finns have been saying for years that while the work the Turku group does in Finland is of high quality *in general*, it lacks the burst/agility part. Rantanen, Kakko and other Finns who follow it look similar coming out of it physically strong yes, but also "square" to a point. Rantanen is physically a moose, but he is also not a greast skater, something he really has worked on this last season at the age of 25. Rantanen has improved noticeably, especially in speed, but he still is wobbly at times.
This is the reason I feel Kakko should work out with Prentiss and the gang, and with the best skating instructor he/they can find.