Okay, I've lived in Las Vegas my entire life. Putting a team here would be a brilliant move for the NHL. I'm sorry, but if you don't see this, you're seriously ignorant of the sports market here.
Firstly, there is a much larger hockey following here than people would think. There's a huge LA Kings fanbase (Frozen Fury, a preseason game between the Kings and Avalanche has been held in Vegas for like ten years straight). There's quite a large NARCH inline hockey community in Vegas (I've played since I was seven). The Las Vegas Thunder enjoyed a rabidly loyal following for the years leading up to the IHL's collapse. The Wranglers, a Calgary farm team, sells tickets. There's definitely a hockey-aware fanbase that already exists in Las Vegas which can easily be built upon.
Secondly, the game of hockey would flourish by moving a franchise to Vegas. I've talked to hundreds of people at UNLV (local college) and around town in general about moving a hockey franchise here. People I would never have thought in a thousand years would like hockey said they would go, simply for the fact that it's a pro sports team finally in Vegas. I believe that portion of the potential fanbase is larger than everyone thinks. Vegas is the fastest growing part of the country, and people have been starving for a professional sports franchise for years.
Thirdly, hockey DOES fit the "tourist attraction" side of Vegas. Hockey is different, alien still, to a lot of the west coast. I can definitely see tourists coming here and buying tickets to a hockey game, just because it's so different and new. Regardless, even if that number is small, so many people come through this city a year I really doubt a franchise would have trouble selling tickets, especially when coupled with the potentially strong season ticket holding population.
Fourthly, as far as an arena goes, I've read a lot about AEG (owners of the LA Kings) already propositioning to build and partially own a brand new hockey arena in Vegas. Imagine something like the Staples Center but on the Strip.
Anyone who doesn't see that a franchise in Las Vegas would be monumental for the National Hockey League is blind.