Though it is marginal to the point you make in this essay, εἶδος and ἰδέα are not the masculine and feminine forms, respectively, of a single term. One is neuter, the other is gendered. While I am not yet certain about their respective nuances of meaning, I am certain that these can't be identical in the consciousness of ancient Greece, precisely because of this differentiation gendered/not gendered.
Though it is marginal to the point you make in this essay, εἶδος and ἰδέα are not the masculine and feminine forms, respectively, of a single term. One is neuter, the other is gendered. While I am not yet certain about their respective nuances of meaning, I am certain that these can't be identical in the consciousness of ancient Greece, precisely because of this differentiation gendered/not gendered.
"Love is soche a might that it makith alle thing comoun."
—The Cloud of Unknowing