Fix healer engagement by healing the enemy (not a joke)

[SamRF]

I don't think healers will get a fundamental change in design, nor does it seem like self sustain of tanks will be changed. The most productive question may be: how can we increase the cognitive load of the healer job in normal/non-heated combat, within the current design?

Since it doesn't seem like healing demand will increase for our teammates, my suggestion is that we should start healing our enemies instead. Well, more accurately, anti-healing them.

Here's how it would work: All it would take is 1 GCD for each healer. This GCD applies a debuff to your enemy target that "marks" a certain amount of hit points. While those marked hit points remain, they take increased damage. Once that marked amount of damage has been dealt, the debuff wears off.

For pure healers, if you cast the anti-heal ability while the previous debuff still has marked hit points remaining, those marked hit points simply increase UP TO the amount of a single cast. So you can't stack more marked hitpoints than one anti-heal's worth, you can only refresh/extend it.

For shield healers it should be riskier. If you cast anti-heal while marked hit points still remain, that cast is completely wasted. No additional marked hit points get added. This means they have to be extra careful to only cast when there's no prior marked hitpoints active. The higher risk should be rewarded with better damage amplification.

Why do I think this works? Well, it doesn't seem to violate the existing healer patterns SE seems determined to keep. Yet it significantly raises the healer skill ceiling and cognitive load (in comparison to how it is now), even in content with low healing demands. Healers will need to be more alert during burst phases (which is where most other jobs get their challenge from - aligning burst windows). They'll need to cast this GCD more frequently during burst and anticipate when burst begins and ends to time the anti-heal optimally.

Besides that, I don't think this would be too disruptive to existing balance since it can be tweaked through damage percentage adjustments without changing how encounters fundamentally work. Though this maybe up for discussion.

This also fits the job fantasy themes, for example:
White mage: Corrupting or weakening the enemy's natural vitality - the opposite of their nature magic healing
Astrologian: Placing a malefic star or curse upon the enemy that draws misfortune when triggered
Scholar: Applying a strategic biolysis-like compound that makes marked tissue more vulnerable to subsequent attacks
Sage: Injecting harmful nouliths or toxins that make the enemy's body more susceptible to damage