Glad to hear you are doing a video guide Rua, but just my two cents on what you said:
Remarkably sturdy would be a misnomer.
Critical defense bonus II is -8% crits, and there is no defense bonus outside of the 20% from the wyvern. Essentially you get a free defender-lite (35%) without the attack penalty. I mean, I would argue MNK would be comparatively sturdy to DRG with the HP, Mantra for the PT, strong magic evasion Su3 armor (DRG and 2Hs in general get junk for magic evasion on gear), etc. Obviously it is no BLU or RUN when discussing being sturdy or not.
Perhaps it is just that Last Resort and Berserk make jobs less sturdy, but that doesn't mean DRG is sturdy because others aren't.
Jump is nice while the wyvern is alive (or you are just weakened) without capping haste/slowed, and boosting the last step of your multi-SC for extra damage or for just ensuring you get the last step off if you are underbuffed/miss. However, in a serious fight with full buffs the gains for it can be close enough to nonexistent.
Super/High Jump would be the very important jumps, and obviously not because of any DPS. Those being the two of the best reasons I find to be a DRG honestly. Nothing beats a nasty move or just losing hate when it is dangerous to have with Super Jump.
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This all lends to why DRG is "still somewhat overlooked" for events.
DRG's uses land in being niche or simply "a viable job" against a few NMs and for midbuff situations, mostly due to the JA haste from the wyvern and then the other associated bonuses. It is in midbuffs situations that it will likely beat most or all of the other 2H jobs.
Situations where you are either not capping or just capping delay with solely haste 2 from a trust or something, and where players aren't capping attack. I mean, maybe you could argue for an Apoc DRK here for fun or just if last resort will last the fight in general, drain 3 and dreadspikes with better attack is a hell of a drug, but lets move along.
Angon is more important for solo play than actual group play IMO; as Angon is more often useless in a fight with real buffs/debuffs before even getting into the fact it competes against other defense down debuffs.
Healing Breath is more often than not useless too. Sure it may save someone, whoopty-doo, but a LOT can happen in 60 seconds. Which makes it pretty worthless as you end up wanting to save it for a significant moment, but then the WHM cures as you hit it and- *fart noise* come back in 60 seconds.
DRG doesn't corner the market on SCing, and leg sweep is merely a novelty item. Sure, someone may use DRG in their low-man group for an efficient SC partner with another DD, but this would be the same as arguing for taking a RDM to such a setup for inundation, etc.
You'd be building around the job as the reason for it's existence in such a case. Not because nothing else SCs, I mean take a SAM or something else with SC bonus/a strong closer for your sequence.
So yeah, DRG is overlooked because it isn't WAR, DRK, SAM, or even THF for piercing mobs. I generally wouldn't ever want a great DRG over a great RUN/SAM/DRK/WAR to DD outside of maybe Teles or something, and I am the DRG in this case. Once again though, why take a DRG over a THF for Teles, THF gets Larceny which is super useful compared to what DRG offers. It wouldn't surprise me to see Rudras averaging better than Stardiver too with Aeneas.
So, I use DRG because I can or because I am messing around. Sure, I can completely drop Strophadia in an Umbra sequence or some easy UNMs, but that doesn't translate to more than "niche" use. Healing breath from /mage was once really cool, but now it would be largely pointless.
Ever take DRG to a divergence boss? Wyvern doesn't enjoy it, and then it sends DRG to the bottom of the pile without it. Even the idea of popping Dawn Mulsums would be a "why stop my DPS, I could go another job". Call wyvern needs to be a 10 minute ability and not 20. Which wouldn't even fix the main issue with the job in that SE made a weaker DD that they tried to cover up by making niche later.
Accuracy bonus largely shouldn't come into play for groups as proper buffs/debuffs are really easy for all DDs to cap. There isn't enough in the way of solid evasion postings outside of T4s in Reisenjima to map out your sets and meticulously use that bonus to eek out another percent or two of DPS on the other end of that. Even then, why bother?
DRG isn't BLU for low end and it isn't all the better DDs or half-witted SMNs for the high end.
Mid-tier situations are sort of like central Jersey. As a region you know it exists, but it doesn't really exist, and doesn't matter unless you say you are from/in it.
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At any rate, the point of discussing jump before digressing all over the place was that DRG doesn't get some higher degree of multiattack over other 2H jobs, and certainly not over WAR or RUN.
Considering it often shares the same gear as those jobs. In fact DRG has it ''worse'' in the gear department than these jobs considering the best options for hands are situationally sulevia +2 or ACROFUCKINGGAUNTLETSin2018.
The only difference in it's multiattack is simply a 15% DA from the wyvern after reaching 1200 job points. Neither a "high-degree" nor a game changer in the multiattack department.
TL;DR:
DRG is something to play because you want to and not because it is "good". Which is why it has always been and will always be rejected and unpopular.
Any DD that is well geared in FFXI is viable. It just doesn't mean people will care about it though. DRG is more of a hobby than a practicality, and people have almost no real reasons to invite or use one other than "my DRG is better geared than their <insert stronger job here>" or "I leik DRG".
Personally, I just leikz da DRGz.