^I agree. There's a difference between Constructive Criticism and Bashing. But if you don't like them, whatever floats your boat...
Me...Otsuka Ai's a well...mixed bag. I love her ballads and do think she has great potential (and think that she's wasting a lot composing songs like ponpon and uboat), but there's something about the happy-go-lucky image that just annoys me, I don't know what...maybe I'm turning more emo everyday...
I don't really dislike any artist...because chances are if I dislike them, I won't listen to them and forget about them and can't name them as a result.
Artist I like:
Ayu
Hikki
Gackt
BoA
Mika
Middle (mixed):
Ai (leaning up the "liked")
Namie (I like some of her stuff, but can't classify myself as a fan)
L'arc~en~ciel: see Namie
Koda Kumi: See Namie also
Dislike: can't name any...