If the NHL is getting to a point where they are using the same teams repeatedly for the WC, then they might as well embrace the same format the NFL has for Thanksgiving games. Always have the same teams play on Thanksgiving/WC and rotate the teams within the league that will play those teams.
It does not make sense to me to not hold the WC in cities where the interest level in the two teams would be high enough for it to be hosted but the national audience would not be high enough. If the formula is that the highest audience would always be brought by teams such as Pittsburgh, Detroit, Washington, then they should be in the game every year. That formula blows IMO. There would be enough people in cities such as Minneapolis, St. Louis, and I'll say it, San Jose, to make it happen in those places. But if that wouldn't bring in a high enough interest nationally, then why deviate from the teams that will bring the highest ratings?