A lot of times, when people look at loot systems, they are concerned mostly with the "fairness" of the system. While fairness is important, there are other factors which are also very important. These include factors such as ease of administration, transparency, error detection, and error correction.
In particular, I think ease of administration is greatly undervalued by the WoW raiding community. Many loot systems are complex, and are not trivial to administer. Often they require you to keep track of 40 people, with people coming and going, and loot being distributed. And it's not an easy task, especially for game, where the officers would like to have fun too.
If you have a perfectly fair system, but it is so complex that the loot officer makes mistakes with it, is it still a fair system?
Even the system I proposed in the previous post is complex. Look at all the elements the loot officer must consider. She must make sure that she sees all the bids, which can be very hard when people are spamming raid chat. She must correctly identify both the top bid and the second-highest bid. She must confirm that both these people actually have the DKP that they are trying to bid with. One mistake in any of these areas, and the fairness that the system is striving for is thrown out the window.
And that's just the spending DKP side. There's still distributing DKP to consider, which is its own headache.
Lately, I find myself more and more attracted to loot systems that are robust and easy to administer, even if they can potentially be less fair than other systems. As long as the system is reasonably fair, I would say that it is good enough.