IMHO:
The NHL does not want to do Canada. Canadian sites will not garner the casual media attention that a US baseball or football venue will. And, since Toronto. Montreal and Vancouver's largest stadiums are domes anyway, its almost a moot point. Most of the CFL stadiums other than Commonwealth (already been there) are not really that big.
Chicago is a little too far south. As others have posted, it could have gone poorly if the weather had been just a little above normal.
Detroit would be great, which would mean the baseball park since the football field is a dome, but playing at the "Big House" would be an even better deal.
Pittsburgh is likewise too far south, and the NFL stadium has an awful grass field and the Steelers are likely to make the playoffs. But a Pens-Flyers game at State College is interesting. The only issue that is that State College is, as Beano Cook once said, tied with Pullman, Washington as the hardest place to get to that you actually would want to go to. Here the issue is bad weather, because the place is not tied to the interstate highway system and is up in the mountains.
Denver seems to make sense.
Minneapolis, when the university opens its new outdoor football stadium (the baseball park is also an outdoor, but why bother) , would be extremely logical. Its probably the most natural hockey market in the US in terms of youth participants and thus knowledgable fans.
Columbus, at OSU, is as interesting as Detroit at UM, but too far south to be safe.
If they are trying to draw attention, Chicago and Detoit could meet again in a few years, at Notre Dame.
New York City just runs too much risk of mediocre weather, although the two new baseball stadiums would be interesting, as would the new Meadowlands stadium, but with two teams sharing it, it would be hard to find time to set up. Rutgers and UConn both have 40K all chair back stadiums, and there is the Yale Bowl as well.
Boston would have to Fenway, because of the Patriots, but Harvard, BC and most of the other too many colleges where too little thinking goes on in that town have stadiums as well.