Well you apparently have time so go for it.
Need/greed is not a system that is prone to have ninja looters in it. Thats master loot and the LFG system can be abused much more than RDF can in that regard.
How if no one is talking to each other? Sounds like a good peaceful time to me as long as others arent running off and pulling on their own which then your group can vote to kick them.
No it doesnt. Being forced to do anything is a bigger detriment than allowing people to have a choice. You and your friends can already group together with RDF in the game.
Yes it does, more and bigger problems than what RDF actually does. Most of the things you attribute to being issues with RDF is actually much larger issues with LFG.