Good question, that is one of the songs I was most looking foward to hearing.
As for Charlotte being replaced with Wrathchild, while I like Wrathchild more, it would have been cooler to see Charlotte because it is so rare. But they probably would have dropped Charlotte for Ozzfest anyways. And now with Wrathchild in the setlist, which is a song normally played at their shows, it could mean a different song will be dropped out for Ozzfest because they have to make the set 75 minues long. It's better they drop Charlotte/Wrathchild instead of something like Where Eagles Dare or Revelations.