This is actually a good thing. Its shares a recast with bloodletter but it is also affected by the reset from the dots. So in an AoE situation you apply your dots and spam wide volley as usual, but instead of rain of death becoming free from wide volley, its a free instant OGC skill when your DOT's proc it. Which from my eyeballing is way more often than it was before.
In some situations, with internal release up and 3-4 dots on mobs, I find myself having unlimited rain of death procs to cast.
Someone correct me if I'm wrong but isn't this better?
Also, in regards to the new song. A smart bard would pop the song during a phase where movement isn't needed, hit Buffs > Barrage > Empy Arrow for 3k+ dmg > Sidewinder for another huge burst hit, then turn the song off until the cooldowns become available again for huge burst.
Instead of looking at this new song as the "new" way to play bard, look at is as another layer, another tool which we may use if the situation calls for it.