Quote Originally Posted by wereotter View Post
Give it to the tanks and you might as well remove it entirely as there will always be a tank in party content..
Give it to the DPS and you might as well remove it entirely. If the point isn't to hard-lock classes into compositions, it makes even less sense to keep them on DPS. Permanent vulnerabilities have traditionally been the realm of tanks in these style of games because it cements them as the primary Assist target, it gives them meaningful damage contribution without letting them encroach on the DPS, and it prevents forced party compositions / exclusion based solely on who brings the Vulnerability.

You get the ability to pick and choose your composition without having to juggle which vulnerabilities are present for you to take advantage of. It's on the tanks, you're solid, grab what you want / play what you want, instead of going "We have a machinist, we need a dragoon"