Relm? Lol. No. Just no. Any character that can equip espers can learn every spell AND gain +2 perm base magic power after every level up if you pay attention to which esper that you have equipped at level ups. You could easily make Cyan your strongest "mage" if you really felt so inclined to do such a thing.
Relm has ONE valuable use: item glitching your inventory by using Sketch on Gau after a return from using Leap.
Friggin Relm. Relm is lucky to sometimes make it into my weakest party for the 12-man triple party in Kefka Tower.
And in FF1, I'd take a BlackBelt/Master Monk ANY day over the Thief/Ninja, as they eventually get even more hits, crit chances, and total damage potential than even the Fighter/Knight; all while UNARMED.