Not saying it's dysfunctional, only that it means that tank potency =\= melee potency =\= aiming potency =\= caster potency =\= healing potency, which is unnecessarily odd compared to having all potency have the same effectiveness (i.e., same output, pre-buffs, at a given stat value).

There's nothing weird about potency increases being locked into traits. Every upgrade is a trait, be it reflected in the tooltips (everything except % modifiers) or not (literally just those % modifiers).