extensional definitions are terribly unsatisfactory

True enough, but it's worth noting that what we have here (between a deontological theory and its 'consequentialized' doppelganger) is necessary co-extension. Less chordates and renates, more triangularity and trilaterality. And it's philosophically controversial whether there can be distinct but necessarily co-extensive properties. (I think there can be; but I just thought this was worth flagging.)