This song has a 25% slow component and does 34 base damage on 65 and is a stringed song. You can get up to ~80 damage a tick and a slock. However, it is a 48th level song, so it only has its moments during 50+ levels. It is also the only AoE song we get with a DoT and a slow, so I believe it is fairly balanced for its level.
I tend to forget this as well, but remember, most classes just replace their spells every "spell level". Bards get a variety of songs that are used in different situations. It may not be great, but sometimes a song serves a role and makes bards more diverse.
Trust me, I do a fair share of bitching about songs, but all in all, they are all fairly balanced and have their place in groups/raids/solo.
Felyn