My thoughts on the DRG job:
At low levels (pre 30) they are one of the strongest melees to have in your party from what i've experienced. They do really nice damage. However, unlike other melees... the DRG's damage curve seems a lot flatter, making them less and less impressive as they climb through the levels to 75.
Also, many people do not notice (Cuz of filters or perhaps just not seeing the wyvern's damage linked to your name in such a way to add it up mentally in exp) the damage aid your wyvern gives. Most of the time, people see what a drg does void of his wyvern.
There's also the weaponskills. Early level DRGs have a decent WS to use- double thrust. That tapers off in the 30s though, leaving them to just be average. When they get penta thrust, the joy of this lasts only a short time, depending on how well the drg is equipped and what monsters the drg fights, what food he uses, and whether or not he has a brd. You will notice that the average pentathrust will only do 100-200 dmg on them crabs and whatnot you fight, either due to hits missing or the crab's def totally nerfing the pointy pricks. When you get wheeling thrust and impulse drive, the weaponskills that people will want you to use to skillchain with, you are dealing with lower-than-average WS damage. In fact, I've read posts on KI forums and whatnot about DRGs using lots of +STR gear and still doing disappointing damage (with or without SA) with these endgame lv3 sc ws.
There's also equipment, well- the lack thereof. DRGs essentially get assault jerkin, or scorpion harness. In fact, the majority of DRGs i see still sport their AF at 70+. Unlike other melees, they cannot equip the haubergeon, which provides both attack AND accuracy, at the cost of something drgs dont really use-- evasion. Scorpion harness will help with the accuracy, but that's all a DRG will get out of it. Assault jerkin gives a nice attack boost, but very little accuracy. Other melees like DRK get buffed by the hauber(k) type armors and thus they end up being more impressive in PTs and such.
There's also just the collective hatred for DRGs ever since TP nerf well over a year ago, where pentathrust's glory of being able to be spammed died- and people began to think that spamming penta was all a drg could do, and they lost that-- so everyone started collectively thinking DRGs are useless. That has lasted to this day.
DRGs have the potential to be great party members, and still deal lots of damage if equipment is tweaked well enough and the right food is chosen. DRG can also lend support with various types of subjob influences on their wyvern's breath (i.e. they can be a healer in pts, especially farming pts) OH yeah, and have you seen a DRG/WHM in ballista-- THEY RAPE ALL. DRGs have their strong uses, but it's not obvious like other jobs-- therefore they are shunned and labelled useless to parties. I noticed a lot of gold ballistars are DRGs. Fafnir, Kileak, and various other DRGs have proven their worth and give DRG a good name. Bruiser, although having an attitude of a tree stump sometimes, was also a powerful DRG in his time. Spyre and Sonfreil also have done well, but have both given up their job for 'better' ones when they realized their lack of use against HNMs/gods/wyrms. (you would think that DRG would be the BEST choice of melee against those pesky dragons, but unfortunately ancient circle and dragon killer dont work very well given the conditions you must fight them.)
I got RNG to 60, and it's really cool=D