Honestly this is one of the smarted decisions yoshi has made.

Think about it, let's say a Thm has Fire 3 and the Blm has exclusive rights to Fire 4, what would happen when level cap raises? How will they give Thm a stronger fire spell at say 65 when Blm has exclusive rights to a weaker spell from a lower level? How will the Blm stand out from thm?

The way he has done it is awesome. Let's say Thm has a scalable Ice spell, then Blm can have a scalable Freeze spell, now when level cap is increased spells will retain their balance cause freeze will always be stronger than ice and black mage will always stand out from thm.