Taking that into account along with the principle of least astonishment, it seems to me that we should be talking about rational processes and motivations used in order to arrive at optimal goals (according to some set of selection criteria) or choose the optimal option out of some set of possibilities. So we'd still be talking about the art of human rationality, but we'd discuss optimal Christmas gift selection, say, or optimal childcare.

That carves space mostly out of instrumental rationality, but I still think there's room for an epistemic/instrumental distinction within the rationality space; the latter would describe techniques and heuristics for practical optimization, but wouldn't necessarily describe their goal.