Similar to Mystic Knight(RDM) and Time Mage(AST) Geomancer does have "a lot" in common with CNJ and WHM for it to seem unlikely. However unlike the other two, Geomancer and White Mage have a lot more unique traits to make a Geomancer job viable. True the Geomancers seen in XIV are very similar to CNJ, but GEO throughout the series have never acted like that, mostly. In the series proper Geomancers usually have access to all elements, and the ability to both set and avoid traps/damage. The way they have been presented in the series as a whole is one of the many reasons I hold out them being implimented as a tank. A lala can dream.