I was in what sounds like a similar situation to you, I never lived in Seattle or the area but the outdoor activities had a very strong allure and I absolutely wanted to live in base. Here's (quite) a few things I considered:
School quality was pretty hit or miss. My only source of school quality was the Great Schools web site, and if I wanted a consistent 9 or 10 on the middle and high school, I was going to pay $200/sf or buy something in need of a lot of work. Not sure if you had a better handle on things than me, but every time we PCS'd we bought more crap and got a slightly bigger house. I effectively priced myself out of the market by "needing" such a big house. I had a buddy move to Gig Harbor and he bought a 100 year old 1500 SF house. It can be done, just not by me
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I hate traffic and being late for anything. This is a serious character flaw on my part, but I absolutely lose it in bumper to bumper traffic. I want to shoot every @ss in the face who thinks he's so important that he should cut me off to move up all of 10 feet. I couldn't do that every day (or even 8 times a month, assuming round trip driving for 4 trips).
The constant overcast 10 months of the year wouldn't bother me, but I'm gone 50% of the time. My wife did not like the quantity of overcast while we were at Spangdahlem and Seattle is worse.
If Delta makes a business decision to leave Seattle you are now commuting or you have to uproot and move your family again. Base closures are a fairly common thing, and Seattle isn't even a domicile (I'm sure I'll be corrected if I'm wrong, but I think it is technically a pilot base). I don't know if the company will even pay for a move if you live in a pilot base and it closes. Moving ain't cheap if you've allowed yourself to accumulate anything near your O-5 moving allowance of 17.5k lbs.
If you still want to move up there, from my research the two seemingly best places to move were Olympia and Gig Harbor. They had the best combination of schools, commute times, and affordability. I ended up moving to ATL, but there's a small part of me that still wonders what if... Good luck!