Loot distribution and trust

I am currently in a guild alliance where the loot distribution is by some sort of top-down system: The player of each class that raids the most gets first pick of any loot, then what he doesn't want goes to the second player, and so on. That is done by a DKP system with fixed DKP rewards for raiding, and fixed DKP cost for getting loot, but with the DKP cost being relatively low compared to the rewards, so getting epic items doesn't change your ranking in the class list much.

The advantage of this system is most visible for the warrior class, the warrior that raids most gets all the epics he needs to turn him into an excellent main tank. For the other classes the advantage is not so clear. Would it be better to have one priest with 8 epics and three priests with zero, or would it be better to have four priests with two epics each? I don't know.

Personally I would prefer a more evenly distributed loot system, for example what you get with a zero-sum system, where the amount of epics you get is directly proportional to the number and quality of bosses you kill. The "main tank" raiding twice as often as another warrior would get twice as many epics, but just not all of them. One reason for me to prefer even distribution systems is that they are more motivating for the players. It is hard to tell somebody that if he raids often enough, one day he will be the next in line to receive all the epics.

But the main problem I have with the "completely equip one guy first" system is trust. I can see that if we all stay together and do Molten Core for a year, we will all end up fully equipped with tier 1 epics. But in World of Warcraft guilds have a relatively high churn rate, people leaving, guilds splitting, or even disbanding. And I think uneven loot distribution is only adding to the churn. Once the first guy in the list is fully equipped with epics, he is stuck. He doesn't get any more epics until the whole guild is ready to move to the next level of challenge, and that isn't likely to happen before everybody else is equipped. So the temptation to leave and join a guild which is further advanced in the raid circuit is big. And even if the fully equipped guy isn't leaving for another guild, why should he still turn up for every boring farming raid which will net him nothing? The risk is high that he either raids less, or even gets bored and quits the game.

In the end distributing loot in a guild is like investment, you shouldn't put all your eggs in one basket. It is better to distribute the loot evenly, so everybody still has something to gain by raiding together, and everybody remains motivated.