Maybe a party with a Nin, Pal, bard, and some fillers if nothing went wrong. It'd wouldn't be that good of a party but it could work.
Mages' roles are to help things run smoothly. Rdms debuff (and removes mob buffs and regen later), blms make things die quicker, and whms buff and heal (and later remove debuffs from party members). Yes, there is a lot of cross over between those roles (especially with subs) but those are the main roles.
I can just see a pre-75 (pre-50 after the expansion) non-mage party shouting for raises a lot...