To me, the bells make then whole atmosphere of the song. Without it, it would be empty. But yeah, it should've been longer.
Best song on the album. I think people are underestimating how easy it would be to play live though. There are two guitar parts, a piano part, and an organ part. The bass part on Roads Untraveled is a pretty key melodic part that would probably need to be played live, so they couldn't have Phoenix play guitar like he's done on Leave Out All the Rest and Hands Held High in the past. So that leaves Chester, Mike, and Brad to somehow cover 4 instruments, unless they were to have Joe sample the organ part or something. The harmonies on the refrain would probably be a challenge too. Then again, given their recent history with their more complex vocal parts, they'd probably just use a backing track and hope nobody notices...
I hate the pre-recorded backing vocals. I stand by LP on every little gizmo and gadget they use while playing live, but I fucking HATE that they use the backing tracks on songs like Iridescent, and it's pretty obvious they do it on Lost In The Echo too during the verses.