Before I say anything I'd just like to say I have been interested in joining and have been just lurking. lol That said...

The problem with Red Mages is that they can already do almost everything so it's hard to come up with something, since they're not supposed to be able to be too strong in anything.

Red Mage --> Red Wizard would work fine. They get a little bit of everything. However if you're splitting Black and Time magic, they lose out on part of their prowess. Maybe make the third Red Archwizard, which gives a bit more of stats all around and allows the use of Time Magic? Or perhaps allow them to become Spell Fencers, gaining the ability to enchant their weapons.

As for Blue Mage...I would ditch. It wouldn't work too well in an rp format, imo.