I feel like BRD and SMN both focus too much on their DoTs considering how their DoTs actually work. SMN, once they get Tri-Disaster, basically isn't a DoT class anymore. With proper rotation you basically never cast the DoT spells and BRD's DoTs, unless you mess up) are just speed bumps before starting your actual rotation.
I feel like DoTs could be so much more interesting, especially considering the buff/debuff stack mechanisms that already exist. Using some ideas from Guild Wars 2, they have Bleeds, Burns, and Poison.
Burns are the highest damage but usually shortest duration and Bleeds and Poisons are close but poisons lower healing on the target (which we could ignore in FF14)
They could have similar types of DoTs that have a chance of being applied during abilities. For example, Straight Shot has a chance to apply 1 stack of Windbite which will essentially be the same as Windbite is, but a little weaker. Additional uses of Straight Shot have chances of adding another stack and increasing the current duration by 6 seconds. The additional stack would increase the amount of damage that it does (not double it, just increase it marginally).
Bloodletter would have a chance to apply a "Bleed" effect that would be more damage than Windbite per stack, but let's say half of the duration. Additional uses of Bloodletter (for example, in Mage's Ballad resetting it).
From there, Iron jaw would still exist and would just reset the duration on both of those DoTs and maintain the number of stacks.
It would need to be reworked so that there isn't a huge difference between your worst luck with procs and your best luck, but it would be a lot more interesting than "Song is almost up, hit Iron Jaw and switch songs."
I enjoy the idea of BRD, but it just seems to be missing something and the DoTs are a big part of the damage (same with SMN), but they just seem to be "tacked on" (same with SMN).