Red Mages are all around good characters. A beginner can have a ball with them. Wear it out like a rag, and then use it as minor assist in the late game.

I don't like the red mage because it never finishes the job. You gotta equip him with the Masmune, in most cases, to kill a freaking worm in one hit.
Ohterwise it's all a wait. Knight attacks Worm, 500 dmg. Worm dies. BB attacks Worm, 550 dmg. Worm Dies. RM attacks Worm, 346 dmg. Worm attacks BM, 140 DMG, BW (Who had lost Hps recently) dies!

I hate having to have another character finish the mess when one combatant doesn't kill a monster that it should have killed. Big problem with this with RM. Even the Ninja has a better chance of not needing assistance than the RM.

Also, the RM has dung for running skills. The fighter and blackbelt and even the WM seem to get more close calls. That, combined with the RMs incapacity to finish what he starts, gives me reason to click to the pure breed class of my preference.

Also, if you're a veteran player, you have no need for the overwhelming power that a Red Mage brings to the early game. You'
re looking for a challenge, not mush. I wouldn't use a red mage on the basis that it's practically cheating in the beginning and utterly annoying in the end.

So that's my opinion.