The main problem is that year after year, Canada relies on "the best defense is a good offense" mentality. Unfortunately, just based on the quality of the teams in the tournament, Canada dipsy doodles around teams like Latvia and Denmark with high octane offense and no defense. Those games are simply a giant game of keep away. By the time they face a team with similar offensive capabilities, they don't have the defensive game to keep up and they get burned. On almost all of the Russian goals, the guys on the ice are just standing around like pylons or making poor changes/poor passes leading to odd man rushes.
Furthermore, I've always believed that the best available players should play. Yes, it is a tournament for 19 year olds BUT that is no reason to exclude underage players if they are capable of contributing and are better then other 19 year olds trying out for the team. Half the really good players (Seguin being the example I can think of off the top of my head) don't even get to play in the tournament because they are in the NHL by the time they are 19 anyway. If they're good enough, let them play. Personally, I think it was a mistake to exclude MacKinnon (sp) from the camp as he could have very well played his way onto the team. He may only be 16 but if he has a better camp then someone else, he shouldn't be excluded on the basis of age.