I agree, I think it will end up similar to this...

Lancer>
Marauder> Warrior
Gladiator>

And then warrior would take away certain skills that would not fit the warrior job, and adds a few warrior specific ones.

Conjuer>
Thaumaturge> White Mage

Both can be whitemages, but their DPS spells are locked out, with the exception of dia and Banish maybe, and they'd get new whitemage specific spells.