To correct your first point, it takes 3 GDCs to get the initial Disembowel up; HT, ID, Dis. No idea what other two GDCs you're using, but I can tell you that you're doing DRG wrong (if you say Phlem and/or Fracture...). MNK can't get to GL3 that fast, as you just said. So there really wasn't a point to this point.
[ except that Perfect Balance -> 3 combo finishers -> GL3. this does not account, however, for the increased atk speed that stacks with each GL. so, yes, monks can do that, if not a little faster.]
Either way, MNK DPS is
still not "8.89% higher than DRG
[again, 8.89% refers to the damage offset of disembowel on a singing bard. that could've been inferred, though, as bards are the only dps class capable, via songs, of a self inflicted damage penalty] assuming both are in their correct BiS and have the same skill with their classes. I don't think the difference in DPS between an ideal SMN, DRG, MNK and BLM
["ideal dps composition" is highly variable, dependent on the fight, and becomes more negligible with player skill.]in idea conditions for each class (since they all excel at something different) is that high either.
Ideally,
no melee is getting hit by any avoidable AoE [given that OP has no experience as a melee, this is highly improbable.]. If one is getting hit, assume the other is
[no. no, you cannot assume that. one melee dodging AoE is not mutually exclusive with other players receiving it.] In fact, I see MNK with more damage after Stomp -> Plumes
[your individual experiences are not indicative of others] because they tend to be out of position a lot more (even the really good ones) and hit by random stuff (whereas a DRG doing the proper rotation will never need to be away from the stacked group during Plumes or LS to be at 100%.
[again, your individual experiences do not reflect the collective] Actually, there's a whole thing about DRG and Titan EX synchronization that's almost scary). So that point gets knocked off.[uhhh.... straight up: what???] And the flaw to the "learning curve" argument: those learning never have the ideal gear, and often don't have the pieces that give the best survivability (read: body and legs), often having "better" accessories or just plain outdated gear, which lowers survival past the point the class differences matter (also, while leveling...DRG and MNK often use the same gear, so the point completely falls apart there)
rephrasing what you've said, roll drg and don't bother rolling monk because - the inherent differences between mnk and drg defenses can be mitigated by equipping mnk gear, except that actually learning how to play a class is dependent on having "ideal gear". most people, however, are not using this ideal gear and thus gimp their survivability. at 50, they will be forced to wear their respective class gear where the disparities in defense will be apparent in their survivability to AoE. this survivability, however, is null and void because ideal team set-ups are common and nobody will get hit by AoE, due to their skill and gear - gear acquired by skill... skill that capitalizes on optimal gear...
here you go! http://en.wikipedia.org/wiki/Circular_reasoning