Yes we will have to disagree. Alzner performed well at those WJC (particularly when he was captain in 2008) in a purely defensive role, which is the role he would take on any significant edition of team Canada. Similar to the Vlasic role, as a defensive defenceman on the weaker (left) side for Canada. I expect that his game also has much room for improvement as well, and I suspect HC agrees given his invitation to the summer orientation camp for the Olympic team.
I agree that it is better for their development (and better for the future of HC) if they go deep into the playoffs, and I am not expecting Colorado to lose until the second round.
I think the way that Canada has picked these teams in recent years has been pretty effective. Pretty much every player on the Olympic roster in 2014 had engaged in a positive experience at the WC before making their Olympic debut. Even players on losing teams (Tavares, Pietrangelo, Duchene, etc.) have put in some very good performances for Canada at this tournament in leadership roles. The crop who debuted in 2010 (Getzlaf, Crosby, Weber etc.) had all put on great performances at the WC before 2010 as well. Unfortunately this year it looks like there are no obvious future Olympic candidates. Rielly looks closest, but that would probably be quite some time.