How to make the "Casters" Unique.

[Bowen]

well in most FF whm had no offensive spells besides holy unless they were part summoner or part blm. but for an example rosa from ff4 pure whm no aero, stone, or water.

Um, no. WHM has had Stone and Aero spells since early in the series.
http://finalfantasy.wikia.com/wiki/W...I)#NES_version