What if tanks got shields and bruisers didnt?

Shields are an incredibly powerful defensive steroid - to the point where the best fighter champions either have powerful sustain or powerful shields. Yet many tanks dont have them, and suffer because of it. So... Short of a sweeping rework to the class to reduce damage across the board in favor of utility and shields, what if we had an item that gave tanks a shield? First things first - this suggestion scales and rewards high HP items. While fighters COULD use this item, the sheer lack of offensive traits and the fact that its a tear item will greatly dissuade them from abusing it.

Mana Manipulator. 2900g. Builds out of + + + 650g 250 mana 600 HP Unique passive: Awe; Gain 1% of your maximum mana as a shield increasing by 1% per 100 bonus mana up to 10% of your maximum HP. Regenerates based on mana recovery rate while out of combat. unique passive: Mana charge. Taking or dealing ability damage grants 5 mana. Transforms at 1000 mana into Mana's Heart.

Mana's heart. 1000 mana 600 HP Unique passive: Awe: Gain 1% of your maximum mana as a shield increasing by 1% per 100 bonus mana. Regenerates based on your combined health and mana regen while out of combat. Unique aura: Mana charge; Your base mana regeneration is increased by 250%. Whenever you gain mana nearby allies gain half of that.