20 str(BC potency enchant) is better than 50ap(new greater potency enchant) and possibly 65ap(new superior potency).
20 str = 25.3 str after kings and divine str buffs and 25 str = 12 block value. So clearly better than greater potency and possibly better single target threat(SotR scales with block value/str not ap) even with giving up 15ap to superior potency.
Am i missing something or are the new potency enchants really that bad?