If you go to Japan you'll immediately notice that the Japanese in general are very westernized (fashion-wise). Most teenage girls that I saw there dyed their hair and wore a lot of western-influenced clothing. I don't think Ayu's any different from these other Japanese girls. I think she's actually a good representative of Japanese fashion and style (well, I don't think most girls have as much money to change their hair as often, but that's besides the point
). So I think a better question would be, "are Japanese girls too westernized?" Japan in general is obsessed with America, and I haven't the faintest idea why.
So to even say that you think her PVs are too westernized would be questioning Japanese society more than Ayu, because many Japanese would love to see a PV set in America.
Granted, Ayu seems to change her hair color/style more than a lot of Japanese female artists, but that's probably just Ayu. She probably just likes having different styles; I can't imagine she's trying to become as western as possible. I don't think that's her ultimate goal (but again, I'm not Ayu so I can't say for sure). If it were, she would never ever change her hair color back to black. And we know Ayu, she's way into clothes and fashion and image, moreso than a lot of female artists (Hikki and Ai-chin, for example). It's just her personality. She's going to try everything.
So no, I don't think she's too westernized. She is a modern Japanese girl. Modern Japanese girls are westernized. This is what I expect her to look like. If you want a traditional Japanese singer you're going to have to listen to enka or classical. That's like people going to Japan expecting to see tea houses on every corner and geisha walking about.
And really, as I said, a lot of it is amplified by her personality. She likes clothes and hair. Much moreso than some other artists. She just happens to like blonde-ish hair more.