Why doesn't Seattle try AHL first in lieu of being an NHL market-in-waiting, like Winnipeg? Affiliate with Vancouver.
This.
The NHL is not going to expand for at least another 5, probably more years. In the meantime, an AHL team in Seattle could build the market.
The AHL would work better as a market builder than the WHL. The AHL is a professional league and the calibre of hockey is a big step up from Major Junior. More importantly however, an affiliation with an NHL team (preferably Vancouver) would carry over to the NHL as people would tend to follow prospects who get called up to the NHL.
As far as travel costs go, I'm sure Abbotsford would welcome another west coast team to split the visiting team travel costs with. Seattle is far enough away that it would not cannibalize the Abbotsford market, but close enough that, if it were the Canucks farm team, Canucks fans from Vancouver would make road trips.
Maybe some day UW will have an NCAA hockey program.