I really wish they could.
All this shoehorning into roles stands for a lack of variety. No real stat jobs, no jobs that blur the line. Traditional FF jobs awkwardly twisted to match one of 3 roles. The series wasn't meant to have 3 kinds of jobs with moderate differences, it's a series with all sorts of crazy niches.

It would probably screw up their instanced content though so I don't see them ever doing anything for that.