You must not see many THF Dragonlord because they are one shotting everything and critting for 4-5k in heroics. But sure, doing less damage then kensai and being given a broken ability makes sense. It's this mentality that keeps the game broken. We should want things to be working correctly and not just shrugging it off. Holding the devs accountable is a major part of any video game.
The poster you're responding to isn't wrong. I could roll up any number of builds with almost any of the class icons that can "one-shot" everything in heroics on Elite/R1 difficulty. That's not new nor unique to Dragon Lords so it seems like they're balanced just fine there.
Dial the difficulty up to R6+ and I suspect Dragon Lords won't be one-shotting things, yet other classes/builds certainly can.
Roar and the group auras are the only thing Dragon Lords have going for them versus a standard fighter/Kensai. Also, the duration on Roar's effect is relatively short compared to most caster-based CC.
They're second-tier DPS versus Kensai and other meta builds. They're second-tier defensively versus proper tank builds and/or evasion/dodge based DPS.
Nerf Roar into uselessness and we'd be better off running a Charisma based Kensai or even Paladin and taking Greater Color Spray from Feydark Illusionist for the same basic playstyle. Run it as a Deep Gnome for a second GCS (assuming it doesn't share cooldowns) for even better CC.