As I stated earlier, the only thing I find strange, is how people relate a Dragoon to mobility, when a Monk has in truth more mobility in the long run. True, a Monk is limited to being at a set range in order to use ST, but Jump is not really mobility for a Dragoon, it is an attack. Dragon Fire and Shatter are our Mobility ( yes you can count Ellusive, but that is not to target ) and on a much longer CD then Monk's ST. Perhaps it is just the option to have more then one.

Dragoon is fine DPS wise, it is a set back to reapply ID or HT, but not the death of a dps encounter. Same goes with Monk and applying outside of designated flank/rear for maximizing DPS.
Both have situations where it may or will happen, both classes survive nicely in recovery.

As to the stat debuff, as pointed out by whiskey, really there is not another stat that is "needed" to be debuffed. I would be more interested in a forced crit effect like Boot Shine, before I would be in a stat debuff. Vorpal force crit when both HT and Dis are applied to target for example.
But that may push the intended DPS of the Dragoon a bit higher then the Devs want in current content.