We are not talking about blm cast times here. My cast times are at present 1.32s. You do not need to stance dance to handle cast timers less than 2s.

Without WM, you drop 30% dps. I main bard and I've yet to come across a fight in any EX primal or savage where stance dancing was needed where simply using Feint didn't suffice.

Toggling off WM puts it on CD, so you cannot immediately go back into WM. You will loose Iron Jaws to reset your burst buffs and your Empyreal arrow. Stance dancing on bard is absolutely never a net gain for any serious bard.