Well, no, because then it's locked into specific trees still. The solution for that was to have spell power applied per AP spent. Positive spell power the same way caster trees are adding universal spell power for each AP spent in any ranger or paladin tree would be the better way to go I would think.
That promotes more flexibility in the trees select without having to worry about the devotion line tree, and promotes more synergy with multiclassing things like arcane bardchers or radiant pallies (even tho that isn't the name of the tree).