In my opinion, the first thing that needs to be fixed is the whole chaos thrust combo chain. No other job in the game is as heavily penalized as DRG is for missing the positional for impulse drive - disembowel. It completely locks the chain up if the target even slightly shifts to the point you are technically off its back. While positioning itself isn't hard, there are way too often many many instance where bosses spin themselves for a random attack, or a tank shifts just slightly to avoid an aoe and you miss. These are factors that 90% of the time are far outside the control of the DRG player and they are penalized for it. Not to mention the combo chain is near useless in solo play unless you can wait for a mob to aoe and root themselves long enough to get the skill off, or stun them. Again things no other job needs to deal with.

Change the positional requirement to an increased potency or remove the requirement full stop. This will help to close the gap between min/max potential.
Also the disembowel buff/debuff is now a joke with the release of Ninja. It really needs to be changed.

I don't think the DRG is bad, but i do think it has moved from being "Acceptable" in any groups to being "Debatable given other options".