As others have said, this race will NEVER move out of Portland. It is a Nike race. Nike = PDX (Beaverton to be exact). While the weather may be PNW weather, that's cross country, and the event is so much more than just the race. The kids love visiting Nike HQ and everything else.
Having said that, I do wonder, of all the places in the surrounding area, why the golf course in the east side flatlands? Why not the West Hills (Washington Park, Pittock Mansion, Marquam Park, Lewis and Clark ...) or Mt Tabor, Sellwood, Westmoreland, Powell Butte, Laurelhurst, Reed/Eastmoreland, ...). There are so many better locations just in the local area. If you select one with more hills (or the volcano) not only is it a better race but it would be much less soggy with run-off