Hey, a quick thought.
Right now, we have the three support items:

Meant for tanky supports that want to be in the frontline and get in peoples' way. Quest reward is a shield that passively recharges out of combat, making their job a bit easier.

Meant for AP poke supports. Gives gold for poking enemies and does a bit of extra damage to boot. Quest reward gives them a phage-like effect that lets them get out of harm's way after poking the enemy -- but only works if the passive goes off.

Meant for utility supports that aren't necessarily tanks or poke machines. Restores mana occasionally, and gives you a good chunk of gold -- but only if you go into minion area to pick up coins. Could be good on someone like Rakan, maybe someone like Taric if you like spamming, or even something weird like Blitz. Quest reward gives an ability point, which could be useful if they have strong base values.
Now, we don't really have a dedicated item for healer supports, do we? What if we added a fourth support item that benefits healers in some way, and gives them a meaning for all their kit?
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(Name goes here)
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Small amount of CDR, and then mana / health regen.
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Passive: Healing or absorbing X damage / health on allied champions grants Y gold and empowers your next heal / shield to be Z% more effective.
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Quest: Healing or absorbing (a large number) on ally champs transforms the item, turning it into a healer's DFG. Target an ally champion and heal them for 100-300 (I donno, pulling numbers out of my ass), and amplify all healing / absorbs they take by X% for the next Y seconds.
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Might be broken, I donno. But it's an item that healers feel good about taking, and it feels good to use it. Add some shiny effect to it, and blamo. Have the 3rd tier of the item have some kind of passive instead of an active, maybe slowly regenerate health in an area (like Heimer's old passive, but a bit better) up to a limited amount that recharges after a while.
I'm not goinna pretend I'm a god-tier designer, but it's an idea. A lot of people complain about no real healer item, so I thought we could brainstorm a bit, maybe Riot would like one of the ideas.