Just because something is a bigger upgrade from someone, doesn't make it always the best choice to give it to them. We used to do Loot Council, but eventually moved away from it in the interest of saving time and less hassle. I'm sure someone can find a way to game most systems. We used to have people not pushing for a moderate upgrade and instead winging it with what they had until a BiS dropped and since they were the most disadvantaged, then it went to them.
DKP at least reflects the time investment people have put in. For the things I most want, I'll bid large. The rest, I scale my bidding depending on how much of an improvement it is for me. If someone wants to go all in to win something, then that's their call. They'll eventually not have enough to buy something when it really matters.
If I lose out on something that I really want, the only person I can get annoyed with is myself for not bidding enough. If they had more in the bank, then I never had a chance anyway.