Mantra of healing is a very good expert for gives support to weakest allies but is useless to help the tank or templar tank 'cuz not allow to use skills and enemy can't keep atacking the tank or can be used for trolling.
I suggest this, 65%/70%/75%/80% damage reducction for 1,5/2/2,5/3 secconds and heals 3%/3,5%/4%/4,5% max hp of the target and slows 90%/80%/70%/60 and not make the ally or templar target invulnerable, also silences target while it last.
Thanks for reading.