Based solely on the headliners, I would've voted against your poster, too, and not due to any malice I have towards you (I really don't have any towards anyone on this board, as contentious as I may sound on occasion) but because none of your headliners excite me all that much. (I like the Pixies but wouldn't cream myself to see them atop a festival line-up.)
I think the budget system and the sub-headliners list probably served to hinder some people's ideas for their posters. I had one day all set up that I had to completely scrap after Thom Yorke and a couple other acts were added to the sub-headliners list and thus caused my festival cost to skyrocket. When you've got only so much money to play around with, it shouldn't be a surprise that some people are going to opt for what they feel are sure bets.