I think saying he should've been in the AHL is dumb, he showed no signs of being ready for that level of play either. "Playing with men" in the Slovak league for 30 games doesn't really prepare you for the NHL/AHL.
Mysak played in both the Czech league and the OHL for half of his draft year and he had similar stats to Mesar. He came over and spent 2 years in the OHL, and now he can't even crack the roster in Laval. And Mysak is way more physically ready than Mesar and is touted for his defensive play and leadership. If he can't play in the AHL, what makes anyone think Mesar is ready?