The SHL is a better league, that doesn't necessarily make it the better league for every prospect's development. There is no way of p;roving that a year in the SHL is of more value to a prospect's development than if he'd played elsewhere. No one should dismiss the possibility that SY was right if it's true he would have preferred MBN to play in GR this year, if only for the simple reason that he would have more influence on MBN'S development than he will have now with MBN in Skelleftea. He also probably knows there is no downside to MBN playing there and in the long run won't make any difference.
When a player has success in the NHL, it's almost entirely a product of his own resources. There are always key individuals or moments that an NHL player will credit for what he has become, but if the player himself had not been willing to learn from that key individual or able to incorporate those key moments into becoming a better player, they wouldn't have led to his NHL success. Other prospects have the same coach, same skating instructor, similarly strong supportive family, same game opportunities and don't make it.
If a prospect has enough talent, the right amount of good work habits, commitment, intelligence, confidence, ability to adapt, he will be successful. If they are inherently part of him, they will not be coached out of him, or disappear if playing temporarily with the wrong linemates or not used on a PP X number of minutes. They will not be lost on a road trip of long bus rides. The idea that a prospect might have had a significantly different NHL outcome if he'd only been given a chance one season with better linemates or promoted sooner or promoted later or assigned elsewhere for a year is mostly just excuse-making by fans who were wrong about a prospect and need a scapegoat.