personally WTTJ is the perfect opener.
Also could start with:
Nightrain
Sweet Child
You Could Be Mine
It's So Easy
Mr Brownstone
personally i dont think its the right time to start with a new song, atleast not untill after the album comes out
Nightrain for the whistle, sweet child for the massive signature riff, you could be mine for the instantly recognisable drums, It's so easy for the thundering bass intro. Mr. Brownstone is debatable, but it does have a very recognisable opening sound.
An opener for a big, GNR type band should be instantaniously recognised by the whole crowd, to create that "yes, this is really happening" feeling. It should send a surge of energy through every single person in the audience, and you can't do that with a new song, no matter how hard it rocks.
As for CD being a great opener when the album finaly has been released, I can see where people are comming from when they say this. At the very least, it starts with what could be a very recognizable riff. The flow and tempo of the song just doesn't cut it, it's an OK song, but nothing groundbraking or earth shathering. The initial kick in the balls that the guitar riff might provide will be drowned out by the less than stimulating tempo. None of the new songs have that "opener" quality. They have other qualities, but aren't "short fused" enough...