For every outside location that gets brought up, there's a serious issue with an existing team.
Ticket prices are not the end all be all they use to be but they're still quite relevant. Several teams in the league are practically giving away regular season tickets. So how does an outside town work after the initial luster of pro sports goes away?
Portland might seem like a nice idea but one needs to look at the Trail Blazers. They're the hottest ticket in town and their team value is 12th out of 30 teams. That's great, now how do you feel a hockey team playing the same time will rank? If you think Top 20, you're insane. The Blazers have been the only major pro team in the city for decades and have a deep history. A hockey team would be lucky to have a third of the success, especially after a 5 year period where you have initial fan excitement. Portland once had an NLL team (Lacrosse), which actually made the Championship in its 3rd season. They played another season actually improving their record and folded afterwards.
Now sure, you could just laugh at the NLL, currently it only costs 3 million to buy into via expansion, however that's kinda my point. Lacrosse is quite similar to hockey, indeed it's the closest major sport to it by a good margin. The prices to go to games outside of Toronto are dirt cheap, and yet a team in a city with few options folded after just 4 seasons.
I doubt Portland would be much of an opportunity, albeit better than Glendale.
I think anywhere from 2-6 teams could relocate in the next 10-15 seasons. Expansion in this context seems highly unproductive.
The NHL expanded by 5 teams from 91-93. We also saw 4 teams relocate from 93-97. Is the same things going to happen now?
It seems unlikely to me for the following reasons:
1. NHL is much more expensive, and there's a limit to how much you can expand with a growing price for product.
2. Winnipeg has gotten a team back and Quebec is expected to follow. While Atlanta lost a team for the 2nd time. It seems unlikely that there could be anywhere close to 9 teams able to take in an NHL team.
I DO however think expansion will happen due to high expectations and extending tv contracts. I think the expansion will be just 2 teams while at least 3 will relocate. In the next 10-15 years. Historically, the league has been extremely quiet from 2001-present, with just the Thrashers moving to Winnipeg. This now 15 seasons of relative peace is set to expire in a big way in the next 15 seasons.