you don't need to fistweave, you can use it for extra mana tea stacks and some of the top end mistweavers were using it a lot for cutting edge progression where dps checks were a real thing, trying to clear the content within the first couple of weeks in 665-670ilvl gear; ie. Skipping an add on margok for a cleaner push, pushing at the start of Ko'ragh to kill it before like 8 balls are about to drop, tectus upheaval stuff like that.
End of the day just play the class how you desire; if you're raiding more casually you don't really need to focus on bringing the deeps just do what you enjoy.