The problem I see with Stamkos is he’s for sure no longer one of Canada’s best players. He’s 19th in points per game for Canadian players. He’s probably not even Tampa Bays best Canadian forward. In addition, he’s most a power play specialist at this point, with more than half his goals coming on the PP. I don’t think Team Canada will need PP specialists.
In comparison to Barzal, well he gets less points, but he’s in a much, much more defensive system (Team Canada brass tends to like players that can play in these systems), and he’s playing with less talented players than Stamkos. The quality of Stamkos line mates and D units will not improve that much from TB to Canada. But for Barzal, the talent difference between NYI and Canada will be very large, and talent tends to have an increasing rate of return. Also, neither one will be playing at Center anyways, so, face off ability shouldn’t impact the decision.
Tavares seems to get a lot of his points at even strength, so he’s got good arguments for him to make the team.