Just this change alone would be a massive start. Example, if we have a boss with a mini tankbuster that happens every 15-20s ish, that forces the tank to use their 25s on it (downtime helps smooth out the gap). Meaning that said tank no longer has a 25s to use on every damn TB. GNBs can get 'almost-literally Nebula' from their 25s if they time it right, because it's 15%+15%. 28ish% mitigation on any given tankbuster or raidwide, and then it ALSO has the Excog effect on top! Sheltron's at 15%+15% now too, and also heals for 1000p over 12s. For comparison, that's the total healing from Medica 2. Being able to just throw 'Medica 2' on yourself every 25ish seconds (autoattack means the timer's a bit weird) is just obscene self-sustain. Could have been 500p over 12s and part of me would say 'wow that's quite a lot of healing for a non-healer'. And then of course, Warrior, SE's favorite child, gets to have 1200p every 25s via Bloodwhetting, plus 400p of shield, plus 1200 from Equilibrium on a 60s CD, plus 1500 via the HOT on Equilibrium, plus 20% effectively when you pop Thrill of Battle and both your Current/Max HP go up (but when the Max HP wears off, the current remains)
Poundland deserves better than this comparison /s
I don't see the irony you are, I see 'BLU is able to function as a healer, with just a core kit of 7ish GCD healing-related skills. The rest of the kit can be damage, utility, emotes, whatever.' This just puts the lie to the current healer design, and the additions we got in EW for some of them. Why did we need Lilybell or Macrocosmos, when we can already solve all the healing required with the kit we already have? Why add Aquaveil or Exaltation when the tanks never seem to take enough damage for them to actually feel 'needed'?
Consider a theoretical WHM styled after what BLU heals with, which gets:
Cure1, 500p/500mp cost, at 30 becomes Cure2/700p/500mp, at 86 becomes 800p
Medica1, 250p AOE/1000mp, becomes Medica2/400p/1000mp at 45
Cure3, 500p AOE/100p Regen on all allies for 15s, 60s CD
Stoneskin, 250p AOE shield, 800mp
Salvation, 1000p AOE heal, 3000mp cost
Absolution, 400p shortrange AOE, removes one debuff, 700mp
Healing covered, now you've got like 18 spaces to add interesting things to the class, instead of having three separate versions of Cure 2, and two versions of Medica 1