Strongest: WHM, BLM
Weakest: MCH

White Magic was the counterpoint to the devastation wrought by Black Mage. While it's primary purpose is to heal wounds and rejuvenate, it was banned due to it's misuse with many White Mages becoming power hungry and using their abilities to do harm. The damage caused by White Magic presented such a problem than the elementals themselves destroyed many White Mages, scrubbing it from the world.

It wasn't until a long time later that White Magic was returned. To heal the Twelveswood, select few were given this power who are now known as Padjal. The offspring of a chosen few would have strong mastery of White Magic and would remain youthful. It's intentionally kept rare so as to ensure it is not given to those who are not worthy of holding such a power.

So, basically the white magic we're using in the game is the tiniest tip of a very large and very powerful iceberg. Same goes for Black Magic. We're essentially limiting our own mastery of the skills to avoid repeating the mistakes of the past. Should a Black or White mage come into the full power offered by the magicks, they would easily match and perhaps even beat Louisoix Leveilleur in terms of raw power.

And I remind you that Louisoix fought the mighty primal Bahamut on equal footing, and at his strongest.