I've noticed this a lot lately and it kinda bothers me. I'm not worried about being top DPS. I'm geared ok (slowly working on DL) and generally hand out around 2-3 on the hate charts even while singing. I know the parsers show less dmg done, but overall the PT does more.
I'm still conflicted with the songs costing MP AND a 20% reduction in damage, but it is what it is.
I typically pop a MP or TP song (I haven't seen the need for enemy debuff one really) along with the boost song skill somewhere towards the middle of an extended fight just to make sure everyone is 100% enabled.
Example: On Ifrit I'll pop TP song if we're melee DPS heavy or MP if mage heavy about 30 seconds before nails. I turn it off the second nails pop. I lose a little total dmg on Ifrit, but the PT gains a better shot at downing the nails.
I'll pop MP if the healers are getting overwhelmed in a fight or TP if we have WAR tanks and multiple adds in other situations. I don't feel as BRD like as I did in 1.0 or XI, but it still give the PT a quick (if temporary) boost.
So why aren't people singing more than the flee song?