I feel like the only restrictions on glamour should be:

A. You have to have at least one job capable of equipping the piece you want to glam onto another.
B. No glams between jobs of course, even if this wouldn't be a potential animation nightmare with job weaponskills/abilities.
C. No glaming artifact sets for other jobs. The once per expansion sets that actually are iconic toward specific jobs.

The role based gear, while there are a couple of trends like 'fending has a bit more armor' most of the time etc, don't really have anything to do with the specific roles, and many like the shisui and sky pirate sets really follow more of a general set theme than role themes anyway. Not to mention level 1 glam items.