The new LFG system is certainly great, but there's one problem with random PuGs that I'm sure it won't fix, and that is of course the problem of ninjas. As long as random people are getting into groups (and with the new rewards system in place, there'll be plenty of that), some of them will always find the loot more tempting than keeping their reputation clean. So what's the solution?
Obviously, over on Guildwatch, we've been covering people shouting out names and guilds on the forums for a while, but as we've also reported a few times over there, that barely helps -- even if people do remember a ninja on their server, one name change later and they're gone. A few guildleaders over on Jubei'thos have tried putting a site together to track known ninjas on the server, but even that has issues; it's tough to avoid false positives, even if you do require screenshots.
But surely there must be a solution, so let's put our heads together: a debuff? Something like the group vote-kicking system that's coming in patch 3.3? If Blizzard wanted to really go for fair, they could just take the Need-before-Greed system and turn it into straight Need: if an item matches your class and spec, you get a roll (with items everyone can use giving everyone a roll), and the best roll always wins. You can turn it off (for a Master Looter-style raid), but for PuGs, why even bother with a Need/Greed difference? What do you think?