Mmu, I totally understand your feelings. I don't think any of us are trying to say you were not playing tactically smart, or that you're wrong about that trap door exit. But we do find the open to be a whole lot of fun -- very tense, very exciting, very challenging, for all of its different flavor and challenges from other varieties of D&D.
I'll second that the prizes are great -- our team's prizes (third place) are the 4th edition core books (by mail, when they're printed) and also to be playtesters. Second place got what we got as well as an armload of books and the massive blue dragon mini.
Success in the open takes a whole lot of things -- thinking tactically about each encounter and the session as a whole, careful resource management (which does NOT mean saving everything -- resources spent well early are as important as resources saved), and a whole lot of luck. Sportsmanship is a factor in the scoring (I imagine this is code for "did the judge like the players"

). But our teams have always felt that we were advancing in large part thanks to some excellent good luck on top of everything else. As a player, I've learned to love the blur 20% miss chance -- fairly often our enemies seem to miss right when we needed them to. In our second round, Howl defeated one of the Brass Guardians single handedly while trying to hold it off, and Galadan kept two occupied while most of the rest escaped. The same sort of luck helped us make it to the finals last year. So, Lucky is truly better than being good.
Still, winning three years isn't luck, it's diabolical. Seriously.
I do hope you'll give it another try next year, now that you know what you're going in to. But I totally get where you're coming from, and totally understand why you might not want to get near it again.
-rg