Actually, rather than changing the names of the roles, I believe it would be in the development team's best interest to create additional roles to avoid broadening the current roles' definitions too much. Particularly, I think adding in a Support role, at the very least, and moving some existing jobs into it, might help fine-tune the definitions of the roles and may allow them to better balance the roles. In this case, jobs in the Support role would be equipped with a moderate amount of power in DPS output and relative power in other area(s), depending on their focus. A job in the Support role might have a secondary role associated with them.

The party make up for 4-man parties would be adjusted to 1 Tank, 1 Healer, 1 DPS, and 1 Support. In this case, although the overall DPS may be lesser than the original combo of 1 Tank, 1 Healer, 2 DPS, since the Support would be allowed a moderate amount of power, I'd imagine that drop wouldn't be too terribly significant.
The party make up for 8 man parties would be adjusted to 1-2 Tanks, 1 Healer, 1 Support, 4-5 DPS. I believe we've been shown that Solo healing has become something of a regular thing as of late, and I think it would be wise to push into that, both to allow healers to potentially have the chance to heal more, and also to allow healers the chance to shine. The Support will be there to help out, so there would still be a cushion for the healers, but not nearly enough so as to trivialize the role.

Regarding jobs which would be moved into the role, out of the 3 current healers, I believe Astrologian would be best suited to the Support role; this would allow them to have a greater focus on their support abilities, and allow them to become a true secondary healer, as is what seems to be their desired interaction with WHM and SCH when you consider the Sects. Leaving WHM and SCH in the Healing role would allow them to be the de-facto healers of each type of healing, while Astrologian could be there to provide a bit of what the team might be missing (if ever) or emergency assistance with healing when the Healer has run into issues.

Examples of jobs from other roles which might fit into the Support role would be Red Mage, Dancer, and possibly Gunbreaker; perhaps Blue Mage, if they could get past the whole Limited Job thing. I'd like to think that they could bring Bard into the Support role, too, but they would need to make a decision on what they want Bard to be; they can either a have sharpshooter, who happens to whistle while they work, or a Poet/singer who happens to shüt. If they want Bard to be a sharp-shooter, then they should keep the development on this current path and keep them in the DPS spectrum; otherwise, bring them into the Support role and bring back karaoke night.


...That aside, it's probably best not to change the name of the role, as anything else might give the wrong impression for the jobs, and then there's the matter of translation and making sure it's easy to understand what the job's thesis statement is.