I understand needing or wanting to change the spirit of fail and clickies giving out *free* spirit lines, however, this reduction makes shaman less desireable. Already, there is little need for a shm. If you want buffs, see sune. Slow? Any mob that drops anything you'd want is immune. Heals? Cleric does it far better.
The spirit line was the one massively defining ability for shm and made it worthwhile to roll one. I would suggest you look at the items, or the custom procs (spirit of fail) rather than change the spell that shm cast with mana that have very short buff times.
Right now, it hardly seems worth leveling my shm or investing aa into it when the chaos pants procs a 90dd for 28mins vs a 175dd for 7min that costs mana.
The spirit line is the main form of dps for shm, and their main contribution to groups.
I hope you reconsider the changes to shm and offload the dps reductions to the items granting cross class skills/spells.