No, it's not. It's awesome.
I remember a fan asking a band member (Adam or Bono, can't remember which) whether or not Mercy was still in the cards for the album and they said yes. I think that the odds of it making the album are very good, especially since the band is apparently using some of the old Rubin songs as well.
Bono said it would make the album and later Edge said it's still being worked on.