I think the new loot system could be great. I don't see what the problem is.
Yes there is a chance you may get absolutely NO raid loot with a party of 6.
There is also a chace that you get 6 pieces of raid loot with 6 or even 12 pieces with a 12 man raid. So who cares. If you are raiding a lot you will get more loot this way, I think.
Not if you always raid with 2-4 people then you may be worse off.
If you are in a guild it shouldn't be too hard to get 8-12 people together.
And as far as the need before greed thing. I don't know why people are flipping out about this. If you are in a guild raid it is still VERY EASY to enforce rolls on loot. Just have everyone look into the chest together!
That way everyone can clear out the non raid loot, and you can roll on the raid loot. It isn't that hard. If you have people in your guild who don't want to co-operate then it is up to your officers and leader to enforce the guild rules.. I don't see the problem.
If you have pugs in the group, just explain the way your guild divvies up the raid loot at the end. I seriously don't think I have run into many people in this game that are so selfish that they won't agree to a guild's raid loot procedures.