I love them both; they both deserve mononomenclature!
I see Morrissey mostly as a comedian (misunderstood ..... I LOVE the Brown Album cover) and through his humour reveals aspects of the human condition, thus making art.
I see Madonna as a bad artist, but an artist nonetheless. She tries, but will never be anything more than she is. There's a certain authenticity to her. Like a friend who sucks at drawing, so she copies from everywhere else, leaving you with trite arts+crafts that you can't help but love cos she's your friend. Thats how I see her anyways. Plus Erotica is mindblowingly great.