I was somewhat disappointed to find a lack of Magic: the Gathering players on LessWrong when I asked about it in the off-topic thread. You see, competitive Magic is one of the best, most demanding rationality battlefields that I know about. Furthermore, Magic is discussed extensively on the Internet, and many articles in which people try to explain how to become a better Magic player are, essentially, describing how to become more rational: how to better learn from experience, make judgments from noisy data, and (yes) overcome biases that interfere with one's ability to make better decisions.
Because people here don't play Magic, I can't simply link to those articles and say, "Here. Go read." I have to put everything into context, because Magic jargon has become its own language, distinct from English. Think I'm kidding? I was able to follow match coverage written in French using nothing but my knowledge of Magic-ese and what I remembered from my high school Spanish classes. Instead of simply linking, in order to give you the full effect, I'd have to undertake a project equivalent to translating a work in a foreign language.
So it is with great trepidation that I give you, untranslated, one of the "classics" of Magic literature.
Stuck In The Middle With Bruce by John F. Rizzo.
Now, John "Friggin'" Rizzo isn't one of the great Magic players. Far from it. He is, however, one of the great Magic writers, to the extent that the adjective "great" can be applied to someone who writes about Magic. His bizarre stream-of-consciousness writing style, personal stories, and strongly held opinions have made him a legend in the Magic community. "Stuck in the Middle with Bruce" is his most famous work, as incomprehensible as it may be to those who don't speak our language (and even to those that do).
So, why am I choosing to direct you to this particular piece of writing? Well, although Rizzo doesn't know much about winning, he knows an awful lot about what causes people to lose, and that's the topic of this particular piece - people's need to lose.
Does Bruce whisper into your ear, too?
I think you're overstating how rational Magic is. Maybe it was 10 years ago before Internet came along and changed everything, but these days everybody netdecks, brute force optimization of decks by playing a lot (online or not) beats any creativity, and number of viable deck types in a typical format got extremely limited (before JTMS/SFM ban, there was exactly 1 viable deck type in Standard, with everybody playing some variant thereof or losing).
The good old days of rogue decks stealing tournament wins are long gone. Feedback got way too fast for that.
Much larger monetary investment necessary to play competitively also stops people from doing funny things. Even the best rogue deck in Legacy needs $1000 worth of duals, FoWs, and whatnot or it will be beaten by differences in card quality - and few people are willing to spend that much on a wild shot at winning.
I'd say that these days Magic requires about as much thinking as go, chess, or any other game. Learn basics, practice a lot to avoid stupid mistakes, learn more, keep repeating until done.
There might be some lesson here. Or probably not.
There's a lot more to magic than just the deckbuilding part. Personal skill in piloting a deck is extremely important.