Actually, turn 1 is stacked in favour of Dragoons. It isn’t just people using a low sample base.
Coil of Bahamut Loot Tables
Above is a spread sheet based on the information gathered
here. Each turn has 17-18 drops which are divided between the two chests. Each chest has a unique pool, so each item can only come from one of the chests.
However there is a HUGE discrepancy in the distribution of items in Turn 1. There are 13 items in the Left chest and only 4 in the Right. This means that the items in the left chest have a 1/13th drop rate (7.7%) and the ones in the right have a 1/4th drop rate (25%). And to compound this 2 of the 4 items in the Right are DRG, making it a 50% chance each run that at least 1 DRG gear will drop. And just to fully summarise Turn 1:
Tank = 30.8% left, 0% right
DRG = 15.4% left, 50% right
MNK = 23.1% left, 0% Right
BRD = 7.7% left, 25% Right
Mage = 7.7% left, 25% Right
Healer = 15.4% left, 0% Right
So DRG gear kinda has double the chance of dropping gear than everyone else. The chest distributions haven’t been fully confirmed for turn 2 and 4. I can’t fully analyse but at the moment turn 2 seems evenly distributed, but turn 4 is slightly skewed to the centre chest having a larger pool. Turn 5 is split 9/9 with weapons and armour (unless the Ancient Shields for mages drop from one or the other chest)