Theres a simpler solution that will fix a majority of the problems / complaints that arise from the RNG system. Do what WoW did. Open up a 30-60 minute window of trading from when you get an item in the raid. Allow trading only between those in the fireteam at the time of getting the item. Havent gotten the warlock chest yet, and one of your teammates just got his third one? Maybe youll pick up something in the raid run that he/she needs. Boom, trade.