Been pondering this for a soft while now, but why not have two Magic tree items that mirror Shield of Regrowth and Ancile (give Magical Damage, Moderate Physical/Magical Protections, and 10% cooldown respectively). The only problem to this thought is having reasonable passives that would make much sense, Shield of Regrowth is easy for Mage/Guardians that can heal, but a Magic Ancile with a flipped passive would kinda be lazy and hard to make a justifiable scenario for.
So what if instead, these two items had Aura effects?
"Magic Shield of Regrowth" Aura: Movement and/or Attack Speed, or have the Aura trigger when allies within it are healed by others or themselves.
"Magic Ancile" Aura: Soft CC cleanse (Support Winged Blade), or Aura shield pulse when you or an ally is below a certain threshold (Support Bulwark).
I'm not sure if this is balanced or if there is a way to balance this, it's mainly something I think could spice up builds some. The only problem I see here is the Magic Ancile ideas, could end up with Mages/Guardians trying to stack it with Bulwark, which wouldn't do much so long as the effects don't stack.
To anyone interested, share ya thoughts, any feedback is welcomed.