Dorian has the greatest power in the end of the books. After Aelin gave up most of her, and if it's only a matter of supernatural powers, definitely Dorian, even if Lorcan had it all. But because Lorcan is a by far greater worrier, he would win in strength.
But just remember, Dorian was power enough to enslave Maeve with his power. If he would wanted, he would have been anable to kill her with a thought. So he even was more powerful than Aelin, at her full strength. She just learned to fight and control her power much better then Dorian ever will
