Toughest thing about WHM, is they want the focus on healing. So if one were to say, let Stone and Aero be part of the gimmick, then it means SE is encouraging them to DPS. As much as I'd like to suggest they use Wind/Earth in some way it can't be in an Offense way. However as I said this, something came to mind and it's something we've seen in a lot of abilities from other jobs. Abilities being upgraded to other abilities temporarily when certain requirements are meant. So imagine if it was as simple as this. 1 Lilly=Single Target, only 1 Lilly is used at a time when you activate "Elemental Presence" -Converts certain abilities which require Lille's to use, can't be used if you have no Lille's and only one ability can be used- Potentially put it on a 15/30 second timer so that it can't be spammed and do the following.

So 3 Lille's max, when you have 1/2 it's a single target but when you have 3 it forces AOE. Overall you would be more inclined to use the AOE of these abilities but there may be situations or emergencies in which you want to use the single target version on a specific player.

So as it stands we have Stone, Aero, AOE Aero, Fluid Aura and Holy as spells that only' do dmg with nothing else attached to them.

Holy=Divine Grace *Removes 1 stage of weakness from player but inflicts them with "Divine Fatigue" making them inapplicable for Divine Grace for the next 5 minutes.

A WHM ability that can be used in combo with Raise to get a player right back on their feet with I believe decent restriction to make the balance just right. If you want to add more restrictions to it maybe make 3 lille's only and only targets 1 person but I think 1 person 1 lille AOE with 3 lille's works in this situation without being OP because of the 5 min Fatigue to use it on the same player again.

Stone=New Stoneskin. Stone IV becomes Stoneskin with 1 lille you can target 1 preson, with 3 lille's you can make it AOE.

Aero(Single Target) =Haste, Single Target or AOE lower potency skill/ability recast decrease on target

Aero(AOE)=Haste Barrier, Self Target barrier which immoblizes healer for a set period of time, the more lille's the longer the duration

Or something to this extent, if SE wants healer's to focus on healer, then give them abilities that replace their damage spells when certain requirements are meant, when it comes to WHM. Since they do need some form of buffing like SCH or AST.