Sounds cool enough. I cannot wait to see all these moves properly once Japanese gamers host some videos. That pic is terrible.
Tons of Smash World Forums members have Japanese Wiis and will be getting it ASAP, I expect some of them will post up videos. If I find any good stuff I'll put it in some of the Smash Bros Threads (I'm planning on making a spoiler thread for those who don't want to know the secret characters.)
i cant see it being Shiek not with the name Twilight Change
Other people think it might be into Midna (which I doubt, it makes even less sense) or cloaked Zelda, which is pretty much Zelda wearing a cloak with a Sheikah symbol on it (a bit pointless really)
It's implied that she'll be transforming into "what Sheik would look like if she was in TP"