An Interesting Clarity "Change" Idea

Clarity: Restores 40% maximum Mana to you and nearby ally champions (180 seconds cooldown). [600 units range]

Just want to stat what Clarity currently does, the idea I will present will not affect the spell immediately, but instead add passives to the three majour mana sustain items that will buff Clarity in their own way. This will give Clarity a unique factor to it and have it scale better, which its usefulness late game is the spell's biggest weakness.

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Athene's Unholy Grail: +UNIQUE Passive: The summoner spell Clarity restores 60% maximum Mana instead of 40% and reduce Clarity's cooldown by 20%; ally champions only have 40% of their maximum Mana restored.

Archangels / Seraph's Embrace: +UNIQUE Passive: The summoner spell Clarity grants a shield equal to 15% of your maximum Mana for 2 seconds; one-third of the shield's strength to ally champions.

Rod of Ages: +UNIQUE Passive: The summoner spell Clarity grants your next basic attack to deal +1% per 250 Mana of your target's maximum health as bonus magic damage; one-third of this bonus damage for ally champions.