Logically your way of thinking makes sense to me, but I'm curious what the best test cases of the counter-opinion are? Who were the guys who had very polished techniques as prospects and who's skating improved dramatically just from filling out?
This is very intriguing because with shooting a basketball...another sporting topic where the technical elements of a player's actions are deeply scrutinized by fans...I am much more sympathetic with the good mechanics + time = good shooter camp. As shooting a basketball is much more of a pure skill thing, where even guys with textbook mechanics...who don't have problems with their elbow flaring out, not squaring up before their shots, releasing the ball after the apex of their jump, poor-arm alignment or hand positioning, an obvious hitch in their motion, etc...can regularly see their shooting improve with increased refinement/practice. Although even in that pure skill action you see guys like Ben McLemore; who has one of the most beautiful strokes that can't hit the broadside of a barn...even after years of refinement.
But skating is much more of an athletic action, where the technical aspect is all about transferring that athleticism into mobility around the ice. So it makes a lot of sense to me for it to be tougher to improve significantly unless there are obvious technical errors to correct...at least when it comes to burst & speed, edgework seems like something that should continually improve for players with continued refinement in a way that it doesn't make sense to me for their explosiveness to continue growing past their athletic peak.
In football there isn't a single thing that fans can obsess about a player's technique with, because technical errors are much more situational...i.e. using the wrong part of the foot to receive a certain type of pass or to shoot from a certain area, not having the touch to bring a ball in, or hitting the wrong part of the ball to drop a pass exactly where it needs to be, etc. There's no one thing for fans to clutch onto and discuss like a hockey player's stride or a basketball player's stroke.
I really can't think of that many... part of why I'm on that side of the fence. Sedins and Getzlaf come to mind, but I don't recall their early years as much with regards to their technique so I might be off base. Recently I'd say Larkin when from a very good to near elite skater by filling out.. not really the same thing.
I think this is a moot point with Newhook, because I truly believe he is already a great skater. It's funny you mentioned Larkin henchy because I think Newhook's game is pretty comparable to him. Anyway, if that's how you guys feel about his skating, that it's good technically but doesn't translate or won't improve, I'll play along and say that is the case with him.
I don't see bad technique+developed physically or good technique+underdeveloped physically as favourable over one other. Every player is different, and every player is going to develop differently. Lots of successes and failures on both sides. Some good examples of good technique+undeveloped players that had a big improvement in their skating after they got stronger: Joe Sakic, Pavel Datsyuk, Duncan Keith, Marian Hossa, Ryan Kesler, Steven Stamkos, Erik Karlsson, Jared Spurgeon. On the other hand there are some players with poor skating technique that just didn't put it together, but were still successful anyway. Guys like Dave Andreychuk, Phil Esposito, Luc Robitaille, Brendan Shanahan, Ryan Smyth, Jason Allison, Andrew Brunette, Scott Hartnell, Bobby Ryan, Milan Lucic, Wayne Simmonds. Neither path has an advantage in my opinion.
You guys seem to watch a lot of hockey, I honestly think it's pretty crazy you are saying you can't think of anyone with good skating technique that has improved it. Maybe it's less noticeable because it's a more natural and gradual progression for a player to start with good technique and get stronger in the NHL than it is for someone to be strong and then fix a glaring issue with bad technique?
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The only critique I can really see with Newhook's skating is that his feet are so quick that his stride can get choppy and inefficient at times. However, a choppy stride can be worked on, the fast twitch that he displays is something you either have or you don't.