I don't get all of these takes that he came to the league too early...
He did fine last year, both offensively and defensively.
We are seeing two things this season.
1. A coach that is coaching a system that works very poorly with Rasmus skill-set. Rasmus excels at two things
a) Skating with the puck through neutral zone and either generate a scoring chance himself, or pass it to someone else.
b) open up lanes in the opposition defense through cycling the puck in the offensive zone and getting involved in the play.
Kreuger doesn't allow defensemen to lead the rush (if a defenseman is leading the charge, they are without a doubt going to dump it in).
The defense is also at all points shooting point-shots, instead of starting a cycle and keeping the puck in the ozone. (This works very poorly for a team that is built like the Sabres, because either the goalie freezes the puck, which means a faceoff , and they are horrible at faceoffs , or you need a strong netfront presence with players strong on the puck, which the Sabres generally don't have).
2. In Frölunda (and Sweden in general) the coaches doesn't bench players for making mistakes, instead they put them in the same situation again assuming that they will not make the same mistake again.
Kreuger has done the opposite, benching Dahlin, done everything in his power to "protect " Dahlin.
This has made Dahlin doubt himself and as a result he has played even worse.
I.e. this isn't Dahlin being in a sophomore slump, or being this bad all along, or being rushed, it's a problem between Dahlin and Kreuger.
Hopefully they can work it out.
I seriously doubt this new benching will help though, more likely make matters even worse.