I'll take an example of why:
Melee hits for 40k dmg
Earth shield heals for 10-15k (After battle fatigue)
40k - 15k = 25k
It is rly rly strong in that sense. Forcing earth shield on one and switching to the other is still a thing, my friend.
EDIT: Tho' with gear the heal will prolly be like 17k while the melee hits for 50-60k. Then u're allowed to complain. PCE
I mean wwhen someone just mindlessly purges its effectively reducing the shamans healing by 20%, seems kinda silly.
Cant really ocmpare it to priests