Form Shift has two uses that I have found (Currently 58 Monk):

1) Shifting to Coeurl Stance during brief downtimes in a fight, between mobs, phases, running to dodge aoe, etc so that you can use Demolish/Snap Punch to keep Greased Lightning 3 up.

2) Shifting to Coeurl Stance pre-pull so you can open with Demolish - Perfect Balance - Snap Punch - Snap Punch - Twin Fangs - Dragon Kick - Snap Punch (Perfect Balance runs out here).

Coeurl Stance is the 3rd stance, right? I never pay attention to that.