well lets think about how it wil feel to play BLU from lvl 1.
subjob choice will most likely be /whm all the way thru dunes, and depending on how abilities are learned or made available by level. BLUs are most likely going to end up a support class, yet may end up an outsider class like BST for much of their careers.
i think it would suit BSTs just fine to have a companion class with native magic skill... and having BLU/WHM could free the BST to sub BRD for CHR bonus and ballad, or if (pleasepleaseplease) BLU can get a main-job refresh ability, the BST could sub WAR, NIN, THF, whatever, depending on the duo's needs.
at the very least, having a BST friend (or when slumming in TooWeak skillup land, a BST subjob) will lend the ability-farming BLU a peek at mob tp and some extra control over the circumstances in which an ability is learned.
