The more I think about it the more I feel the KO should absolutely include a bracket playoff.
Make the first two days a high score competition, then cut to a top 8 bracket playoff for the last day.
By only including the top 8 qualifiers in the bracket playoff, a lot of the aforementioned problems with boring play and low risk strategy actually begin to make things very interesting...
Do you really want to run boards against someone who qualified with a 1 million plus score? OK, that's fair, but the million player can easily outpace the board runner so long as they survive. In fact, the player running boards runs the risk of having their game end earlier than the point-presser (either because of seeing more bad rivets/pies or hitting the killscreen in less time), at which point the point-presser can just cruise in for the win. Similarly, if both players decide to run boards, the more efficient player will still win out, and the point-presser can still turn it up at the end if required.
Whether or not the bracket playoff should be single-elimination, double-elimination or best two-of-three will depend on how much time we have to run the competition, and that decision will ultimately fall to the organizers.
I agree it would suck to have your day end early due to bad randomness on the early barrel boards, so I'm inclined to think a double-elimination bracket might be best, as two-of-three would just be too time consuming and tiring.
My 2 cents.