It's actually hard to even speculate that this won't happen. It's a near certainty that it will not. Adding numbers to current compositions entails having to adjust previous content as well as new, and as a healer main I can personally tell you that I do not want to have to keep an eye out on two additional players in 8-man, and 6 in 24-man. PUGs are freakin rough man, and a total hit or miss.

I do understand where you are coming from though, and DPS roles are by no means created equally. Even inside their respective sub roles there is a balance and diversity the devs are challenged to maintain. However, it's not content or composition design that makes queue times so much longer for DPS jobs. It is simply a matter of so many players choosing this role. Even tank and healer mains have fewer jobs to level and eventually start playing DPS jobs. The same cannot be said for DPS mains out there choosing to play tanks and healers. Not only because of the increased responsibility, but also the number of DPS jobs available for them to play.

I agree with the others, and believe dividing up the DPS types for queues will only increase the time you spend in it.