Whereas (and let's hope it stays that way for a while), Seattle has only Hawaii in its Oceania flight roster - along with YVR,
Vancouver already has Manila, Sydney, and Auckland. Seattle does not. Add Brisbane and Melbourne in maybe the next five (hopefully fewer) years,
and you'd get five Pacific destinations that Seattle doesn't have.
Also.... although the Paris-Tahiti Great Circle rout goes DIRECTLY through LAX, via YVR it is only 50-something miles longer !! (... $$fuel, you know) ...
Please observe the links if you find that hard to believe:
http://www.airmilescalculator.com/distance3/cdg-to-lax-ppt/
http://www.airmilescalculator.com/distance3/cdg-to-yvr-ppt/
We might get at least seasonal flights to Tahiti if AF decided it was worth it, and a normally lower $CAD (if that works out as cheaper tickets than from the US)
might attract people from Seattle and Portland for South Pacific flights in general, and that's a solid air market, (even just Seattle and Vancouver, if it came right down to it).
Then, Vancouver would truly become an Oceania hub. Wishful thinking, perhaps? Feedback appreciated.