I'm the one who said how different the music sounds, bobbybaby, and I'm not involved with the production either, though I know several people who are. I've just seen several incarnations of it since it came back to fruition (the first reading of this version in 2009, a lab that showcased many of the changes at MCC last year, and the public "preview" presentation they held in August,) which is how I'm aware of what's so different.
The song list from that initial reading should be relatively intact, if you want a sense of what's there going into January 31. The labs have been more to work on book changes and staging ideas. They're pretty happy with how they've re-crafted the score, though I expect they'll continue making changes diligently in previews.
Tonya Pinkins: Then we had a "Lot's Wife" last June that was my personal favorite. I'm still trying to get them to let me sing it at some performance where we get to sing an excerpt that's gone.
Tony Kushner: You can sing it at my funeral.