I'm only (almost) lv55 on Bard and been playing around with WM - and not really enjoying how it feels.
I wouldn't mind it so much if it truly was an option for us to have the song up or not - but locking behind skills behind it means we are expected to have it up - as switching it on and off results in even more loss in dps as every song is 3 secs no matter what you do >.>

In my FC - our best bard who's played the class since day one and was proud of being able to keep up his dps numbers in end game content is now switching his main class as he just doesn't see that Bard is offering as much as it used it. And machinist is in the same boat - which isn't too much of a surprise since they've tried to make the two classes able to be swapped out for one another etc - just resulting in two 'support' dps slots that really are just seen as taking up a slot instead of offering any real type of support or help towards fights.