Still sounds just like buttah.
Okay... I am officially crazy for saying this, but I think it's telling that they dropped the key for this. Steven Tyler is perfectly capable of singing it in the original key. Christine probably is too. Stevie and Lindsey? Not so much. So perhaps Christine has been practicing playing the song in a lower key intentionally with the thought that she would eventually be playing it with Stevie and Lindsey? Although she could probably play the original DS in her sleep, playing it on the piano in a different key is tricky; it definitely took some practice.
This is just so surreal- seeing/hearing Christine in 2013. After refusing to join FM onstage for the last two tours, I assumed something must have been amiss with Christine- maybe she was ill/frail or couldn't sing live anymore or can't walk/stand, etc. Or perhaps she had become paranoid about her appearance. But now this- Christine is doing her thing and looking/sounding like the past 15 years didn't even happen. If I were a betting person, I would wager the house that she's going to pop up at one or more of the UK shows.