I hope we will hear some "new" music in the new documentary. And I hope one day we will also get some more Meteora demos with vocals. At least "Soundtrack" with some vocals exist.
"We tried different vocal treatments, but they never really panned out; I think we felt this track was a bit too poppy. We tried turning the guitars up really loud to counterbalance it, but at the end of the day, this song didn't make the cut." - Mike Shinoda about "Soundtrack".