I think MISIA is an amazing artist, and I think she deserves to sell better and is kinda underrated sometimes. But at the same time, her music, like the also amazing Chihiro Onitsuka, tends to get boring fast. They both do too many ballades, and I think the lack in variety or anything really 'WOW!' makes the 'strong-ness' fall flat.
Also, as great as MISIA is, I don't consider her an avex diva.... Not by the standards that seem to need to be met, at least. She never had the unbelievable popularity that the three definite divas had/have.
And Ai Otsuka....? Even though she had a GREAT few years back in the day, I don't see her as a diva at all. Not even the popularity she had can save it. That's just not her type.
Ami Suzuki was a fad, and she doesn't deserve "diva" status in any way, shape or form. Simple as that.
hitomi was kinda the **** back then, wasn't she? XP So, back then, yes, she could have been considered one. But now... Well, you see her.
Sooooo. As most of us have agreed, Ayu, Namie and Kuu are the divas. Ayu being the diva of divas, of course, hah. Don't know, honestly, who would be after her, though. :O If we go by current popularity, or even overall popularity or sales, obviously it would be Amuro. If we go by talent or even who's more diva-ish, Kumi wins by a long shot....... We'll just say they're tied. XP