The thing is, I'm not sure he really has gotten better defensively. The team, as a whole is playing a simpler and far more dedicated to two way brand of hockey, with much better outlet options. All young players will make the odd blunder but its really hard to tell if Kylington is making smarter decisions or just has far better support.
I think he's making much better decisions this year.
It helps that this team is playing much more sound defensively, but the lack of panic in his game is miles ahead of where it was not even a year ago. A few nights ago, he had that fall in the neural zone with the puck.
Last year, he would have done one of two things:
1) Tried to finesse the puck back to his stick, fumble around for a few seconds, leading to a clean breakaway or 2 on 1.
2) Taken a penalty on the person about the blow by him.
This year, he doesn't panic, he gets up, and fires it deep. He's easily been the most improved player on the team, and if the NHL did a most improved award like the NBA, he'd be right there with some of the other breakouts we're seeing. I love to see it, I was critical of his game because he wasn't a regular, but man, did he ever put in the work and make himself into a bonafide top 4 NHLer.
His gap control has come along, and his positioning is phenomenal. If you watched him in previous years, he'd use his skating to make up bad defensive positioning; this year, it's just sound. He knows where he needs to be. Yes, he still makes some mistakes, but that's where the skating helps negate those instead of relying on it. He still feels out of control sometimes, but, you take it if he keeps pilling up points.
Would love to see him on the PP soon. Although the PP is working just fine, it'd be nice to see other looks on this roster.