Not quite as simple as it looks on paper to balance. The competing healers in both the pure and shield categories would need to do equivalent amounts of raid contribution (either via their utility or their raw damage) while also sharing equitable healing capabilities. Precedent is AST utterly dominates WHM when it comes to both their utility and their healing kit. WHM has no answer to the card system—their raw damage is finally good enough to compete with AST’s rDPS, but this was not the case in HW or SB. As for their healing kit, AST’s is extremely versatile with the amount of oGCD healing it has. Contrarily, while WHM has good burst healing, fight designs rarely call for Cure III spam anymore. Then there’s the issue of clipping with WHM where as AST has a shorter cast time to alleviate the clipping it experienced with cards (and, by extension, oGCD usage).
All three can clear whatever content they want. But there are still nuanced issues that could stand to be addressed that do affect balance. The healers are closer to one another this expansion that ever before—but all three also lost a lot going from SB to ShB in exchange for that.
Um. Why is leaving a job overpowered your solution? Just because WHM was taken for early prog in HW doesn’t mean AST should have kept 10% AOE Balance going into SB. When the developers didn’t revert that back to 5% at the start of 4.0, even raiders were like “uh....”
I loved the old card system. But Balance needed to be addressed because it was just too strong. Unfortunately the solution they chose was to simply the system down to all mini balances but there’s no way they’ll return to the old cards so... I’ve made my peace with that. Doesn’t mean I like the new system, though.
Causal players also never complained about the percentage of ASTs versus WHMs in speed runs because the vast majority of casual players ignore that kind of stuff. They simply don’t care. So I don’t know where you’re getting that idea from.
Even if all jobs can clear Week 1 Savage or Ultimate doesn’t mean you should let some remain overpowered while others feel like garbage—and have garbage damage to go along with it.