My only issue with WM is the name and the lore behind it.
It would make more sense if it had something to do with the strings on the bow. Tighter strings would require more effort to shoot an arrow, and that would call for a charge/prep time instead of calling it a "cast time". Logically it makes more sense that way.

And "able to sing with other songs" is ridiculous. Have you ever tried to sing 2 different songs at the same time? Go on. Try it now... i but it didn't work out very well.