I'm not opposed to classes having multiple jobs, so long as the base classes were built from the start to do that (ACN), ACN gets a straight up Heal spell and a Raise spell, as well as several skills and traits that affect healing.

To make the Gladiator a DPS Job, you would need to rebuild (mines 23, so I'm basing skill numbers from this) a minimum of 9 skills, and then retool a further 4. And thats not even considering whatever i get as my level 30 skill, which would probably bring it to 10 skills needing rebuilds.
Add to that, of 11 Traits, 9 would require complete rebuilds to work in a DPS Role.

At this point, you already rebuilt two thirds of the class... You may as well just go the last bit and make it a standalone class.