In addition to that, why are the -ja attacks carry less power/cost less than their -ga counterparts? They are supposed to be moar elite.
Atm spells are balanced around their tier and area of effect, not around names. In case if you don't know, in most FF games the weakest and the strongest spells target one enemy, and all others target all enemies.
In our case spells can target one, any one, all, all in the first row. If you insist on exact copying of FF spells, our system will be much simpler than it can be thanks to the rows.
Moreover, FF games already have less elemental spells than we, so they can afford a rapid increase in spell power, while we cannot.