I'll explain why pitchers parks don't have an advantage over hitters parks, even though zero of you will understand it, especially if I make a spelling mistake...
When you choose a hitters park (especially with a high portioned offense), there is a much greater deviation in what your win% can be. You can win a lot more games or lose a lot more games than in a pitchers park. Pitchers parks have inherent parity built into their natures. The reason comes from the nature of OBP. Because it is exponential in nature (cencerning scoring runs), a high-end winning owner, will win even more because of his +hits park choice boosting his teams OBP.
Average and below average teams in hitters parks are at a disadvantage because of having to draft more innings/PAs, but playoff bound owners are not.
Several people will now follow my post with examples of how their winningist (misspelled!) team was in a pitchers park, but thats merely because they are easier to comprehend and manipulate, however the principle I stated above is still there. If you know how to handle a hitters park, the advatage you inherit will more than counter what you lose by having to draft more stuff. No doubt about it.