But you also make the skill a non-factor for actual usage.
Basically you'll likely just press it on CD (With Shell macro'd to a tank) and with 50% uptime you'll likely hit most damage with it.
Because it's literally the reason why WHM is seen as unfavoured compared to AST.
But it isn't?
There are more Earth and Wind spells in the game than just Stone and Aero.
Next you're going to tell me that Flare should be single target because "That's what Fire spells are in the game hurr durr"?
If you're just going to make Quake and Tornado into buffs of Aero and Stone, at least don't ruin any chance of making actually good Quake and Tornado spells and just call your crap "Aero IV" and "Stone V" since that's all they are.
Making them instant does not remove the handicap that makes them sub-optimal. Instant casts still use GCD's. That is why RDM isn't tossing out Vercure all the time. That's why you only cast Regen when necessary and don't spam it out when Medica II HoTs will cover the healing.
GCD heals are not wanted because using a GCD on something that is not a damage spell is a DPS loss. It doesn't matter if it's a hard cast spell or and instant cast spell, either way it eats your GCD.
In addition, you now reduce both your DPS AND HPS by using a hard cast Cure I or Cure II in this case (Also, make a case to no longer use Cure III) because without using Cure spells you don't use GCD's on non-damaging spells but you also get to have all your Lilies turn into CDR on your oGCD spells (Meaning, more damage from more Assize and more healing from Asylum/DB/Tetra)
Meanwhile Freecure is still garbage since, you still don't want to use Cure I or Cure II ever.
Really all you're doing is further cementing the current playstyle of "Ignore Cure I and Cure II, spam Stone and Aero's" but now get free cooldown reductions on your actual heal spells passively by doing your normal stuff.
Lilies are still a mechanic to ignore, because you won't go out of your way to actually try and stack/use them. Cure spells are still ignored because there's still no reason to actually use them and in fact more reason to actively ignore them. Your DPS gameplay also doesn't change at all because the "New" spells are literally just extra ranks of the same stuff you already have.
There's a difference between "Simple/Easy" to play and "Not actually changing a damn thing"