"Let them develop" - Cheese is Price. Stop!
The best development possible is in the NHL.
However, if a player is not good enough for the NHL he UNFORTUNATELY must develop elsewhere first, even if that means he develops MORE SLOWLY. Then when finally ready he starts in the NHL in the bottom 6th or bottom 3D. This step cannot be avoided by sending a good player down to dominate weaker players. Anyone not named Crosby, Ovechkin or McDavid starts in the NHL with lots to learn and improve.
If Rasmus Dahlin had played only SHL and AHL from Sept 2018 to June 2022 (his 18, 19, 20 and 21 year old years), would he be a 1D in the NHL today? Not a chance.
I repeat: The best development possible is in the NHL.
It's LUDICROUS to believe that a player (who we assume for the sake of argument is good enough to play in the NHL) is going to learn more competing against Swiss league stars like the washed-up David Desharnais, and getting coached by people who DREAM of working the NHL but aren't good enough yet - than learning from MSL and Adam Nichols and watching Matheson and Savard, and learning to strip Suzuki and Caufield of the puck in practices.
Now if Reinbacher is not top-6 or even let's say top-5 coming out of camp, then he needs to go to a lower league to keep progressing as best he can. Personally, I believe the AHL is better than the Swiss league if the goal is the NHL, and I don't give a crap if Trudeau or Tourigny can't keep up in the AHL because RB an Maillous and Struble and Keeper are getting more minutes.