She looked great at that performance, but I can't stand the way she sings Ai no Uta!
She has been pulling it behind tempo, almost trying to make it grander and more dramatic for many years now. When you go back and listen to the original recording, it's much peppier, and has a bright, skipping heart quality to it. It's a quicker tempo than most of her other ballads, but she doesnt sing it that way live.
Her voice sounds fine there to me too though. Not like she has a cold or anything.
The whole Yume no Uta thing is really too bad.
That's one of my favourite ballads from her, and I'd love to hear it live again.