What sort of capstone trait for level 80 would change how a Job approaches its role, and how would you like to see it implemented?

As a couple examples

Ninja: Virulent Poison
Trait
Effect: Direct Damage Abilities inflict a 12 second DoT with a potency of 35. This stacks up to 3 times.

Something to give the Ninja a little more oomph, but requiring a bit more forethought to their ability use. The goal is ultimately to keep a fully stacked DoT rolling as long as you can, as any reset point not only requires building it up again, but having the abilities on hand to do so.

Dream Within a Dream serves as a powerful starting point as it strikes three times, with Kassatsu, Ninjutsu, and Ninki abilities becoming the extending factors. Ideally it's not a DoT with 100% uptime, but maximizing its uptime becomes a key factor for pushing damage as a Ninja.