I was liking Symbiosis until i read it was a 6sec cast. That pretty much renders it useless for me. Some are really handy in raid situations like the ones that increase longevity. I don't see myself standing still and casting for 6 seconds in pvp/arena/bg without getting an interrupt and even if i did get it off i don't think it would help me in anyway that i couldn't of helped myself in that six seconds.
In terms of questing its useless since it requires someone else to be present - maybe if you had a friend but i doubt everyone has a friend for everytime they quest. Now i think about it i would prefer a 87 spell i could make use in every situation. Honestly i don't see this going live.
This would be better if it was more fun spells we received like levitate from mages, shadowstep from rogues etc but with a short cast.
Im sure this is not all set in stone but ill i hope it does change.