I always liked Kes. She was pleasant and beautiful, and I agree that her voice was magnificent.
Kes is sort of like a hybrid of the Manic Pixie Dream Girl, but without the Mania, and the Mary Sue, but without the overbearing or (I'm assuming) author avatar parts.
One of the points where Voyager
approached distinction, in terms of the drama it brought to the table, was the flirtation that Tom and Kes had. I consider it a missed opportunity that VOY couldn't bring itself to depict Tom and Kes having an affair, at least outside the fig leaf of an alternate future. Flawed characters, thy name is not Star Trek.