The drums are at least on medium in the video, and guitar is at least on hard. There aren't 3-note chords on medium.
http://www.youtube.com/watch?v=Nq8pxhzWeRw some people rocking out to "what i've done" at the games convention in leipzig. shows a bit of note chart (song starts at around 2:30 min) video has quite poor quality
If that's on the hardest setting, then if you can play the first 2% of the song, then you can play 98% of the total song =P I think their setup at that place looked cool lol
I think it's safe to guess this will be one of the earlier songs in the game, if it hasn't already been confirmed as such.
I was told on another gaming forum that In the End is confirmed as a song for Guitar Hero: World Tour on their official site. I went there and couldn't find anything, but out of all the track listings I've seen lately, both In the End and What I've Done are both in the game. I think at least one of them would be some sort of bonus song, though. Guitar Hero III had a crapload of bonus songs that you could buy or unlock by earning money through the tour.