Kansas City
Seattle is a great city for professional sports. Population, disposable income, etc. A good example is the Seattle Sounders which is the most successful team in the MLS attendance-wise averaging almost 40,000 in every game. However, for me, the next professional team to come to Seattle would be an NBA team. The people of Seattle are still heartbroken from losing their NBA team.
I'd go for Kansas City for the new NHL location. Every city that wants an NHL team needs a new home to play in while KC already has one. KC has changed a lot in the last 30 years, its now ready to support a new NHL team. :nod: