You wrote alot here and while I agree with several of your points there are some I don't agree with so I'll just focus on those in the interest of trying to keep this short. I'll admit however to being over dramatic in saying DRG is the worst melee of the bunch. While it is noticeably inferior to Monk (as is NIN), it probably is slightly better than NIN or at the very least on the same level so I'll agree with your ranking.
Ordinarily I would whole-heartedly agree with you on this. However, I am not sure of the prevalent ranged dps over there on Aether, but over here MCH is by far the most common ranged dps you will encounter in feast. This job specifically is the job that really exposes Dragoons lack of mobility (relatively speaking compared to mnk/nin of course) as it is the only dps in the game currently with a knockback running on a 30 second cooldown. As a dragoon its much more difficult to keep up with a mch because of this as unlike mnk/nin dragoons do not have the benefit of a 30 sec gap closer nor the enhanced movement speed to eventually run them down again. Not saying its impossible, just saying it is indeed very noticeable in this scenario.
Bloodbath and Life Surge while indeed useful and powerful, still requires you to be actively engaged and attacking someone to even have any effect unlike fists of earth/shade walker. As such it suffers from the drawback of being rendered useless if the opposition is coordinating CC on you while bursting you (stuns, knockbacks, blind, etc). Keen flurry also requires you to be facing your target i believe in order to even be able to parry so its nowhere near as useful imo as shadeshift nor fists of earth in dmg mitigation as its not as consistent as the aforementioned abilities. Dragoon definitely has the worst tool kit among the three melee in surviving bursts because of these reasons.
Atm the only real edge DRG has over the other 2 melees is their burst which when all cooldowns are available is the strongest of the three. However their burst has a longer cooldown than monk so I wouldn't necessarily say monks burst is worse anyway. Battle litany of course is also awesome and feint is nice but it ended up getting nerfed because of mch/brd.