So they just outlined that in the Raid Finder, Need before Greed will give a +100 to rolls of people flagged for a specific role for loot intended for them. It's certainly a better solution than the pure chaos that straight need before greed would be with 25 strangers, though as pointed out in the comments, it still has flaws.
Again, having to implement this kind of fix shows flaws in previously implemented "convenience" systems. Putting Disenchant on the same level as Greed completely ruins Greed as an option if you actually want the gear for an offspec or whatever, but aren't in the role at the time. Settling a dispute is easy enough (or the loot is simply inconsequential compared to raids) in 5-mans, even with random people. At most, you're likely only dealing with one or two other people who would have any interest in the loot at all. The problem balloons with 25 random people who have less accountability.
Using a trusted master looter, who is at risk of losing reputation if he fails to uphold the contract between him and the other raiders, is certainly the best way to raid when dealing with people on your server - even if you are basically still just doing need before greed. That doesn't work cross-server though, obviously.
The only other thing I want to touch on is that having to further differentiate gear (we already had the mastery bonus locking you into an armor type) for the purposes could be considered dumbing the game down, making gear less meaningful since you will have fewer choices. Protecting the idiots from themselves I guess, if Warriors and DKs couldn't roll on Spell Plate - so not necessarily a bad thing. Though I do worry that it will be too limiting and prevent some creative gearing strategies - again this is probably not a big deal since the "real" gear/progression will still be with guilds and not in the raid finder, so you can do whatever there to be most effective.
Still, it's kind of an ominous sign - we're already sort of seeing WoW transition from a lobby/server based game, to a matchmade game. For all the benefits of matchmaking, it's a deathtouch to the soul of an MMO - the social aspect. WoW is just as much about interaction and overcoming social challenges as it is raid bosses (to me at least, and I think a great deal of other people). I hope Blizzard doesn't forget that.