How will loot distribution work in 24 man raids???

[Zetsumei_Tsunarashi]

Yoshida said for large scale raids you will have a limited number of rolls you can use per instance and these will reset after a certain period of time (Like a week).

This system is basically like a type of dkp that is integrated into the game. It ensures that the same person cant win all the loot every run and also discourages spamming content.

This was covered in a Japanese interview last Fall.

Here's the dev quote on the subject.

As for the number of drops, yoshida gives 2-3 drops per boss as an example. The difference from WoW though, is that only your rolls are on a weekly timer, you can enter the instance itself as many times as you like. So even though there are still only a limited number of drops, you can keep retrying the instance until you have used up all your rolls for the week. This is ideal if you are targeting a specific item and it only rarely drops.

On the downside, a system like this will make it difficult for pickup groups to form, because once a person has used their rolls for the week, they will be unlikely to participate in any runs. This will force most people to do only LS scheduled runs so that everyone does the instance when they have rolls available. Because of this, I would imagine some LS would still resort to using a DKP type of system in order to control who wins a specific item or even who can use a roll, since everyone in the LS will have all their rolls available during every run.