>>212535680Trinity is necessary to fill all criteria of Godhead. You need a person so pure that he took all the sin. Making Jesus a man would make God a bad person because he just created someone who suffered all mankind's sin. Making Jesus a spirit would also be bad because a spirit isn't on the same level as man, so it can't "die" for men. Ignoring the Holy Spirit is bad because he's the abstract concept of divinity.
Women preachers died out because early mendicant duty wasn't yet defined and because women in a religious role mostly serve as either caretakers or seers. By not being preachers, they can devote themselves to charity, and Christianity as a legalistic religion does not need seers to complicate the law by making more prophecy out of thin air.