Niku is a young, established defenseman at the North American professional level, which is the complete opposite of Norlinder, who seemed to struggle in the rookie games. While for Guhle, seasons of development in the minors won't hurt him. Niku is more experienced, but also older, which will make a difference when the Habs makes decisions.
Mattias Norlinder is bound to return to the Frolunda team in Sweden, while Guhle will likely return to the Prince Albert Raiders in the WHL. They will have significant responsibilities with their respective teams, which probably wouldn't have been the case with the Habs... yet.