To be honest though, in some situations, AST would still have better controlled burst than WHM...
Shameless plug here: I think the massive healing buffs should be to a degree rolled back. All that has ever been needed was better usability of cards. However, I believe that includes the need for each card to be more usable as a means of healing, or even entirely versatile. Take Balance for instance. What if, rather than increasing damage by 10%, it simply increased your primary stat by 8%? Now it's healer- and tank-usable. Alternatively, you have Bole, which similarly was useful only on and for tanks. What if it allowed a portion of overhealing to "bloom" onto nearby allies, or caused the target to partly share health pools with nearby allies? Now it becomes useful either for non-tanks as well, or even on low-HP non-tanks.
Arrow already has this function to some degree, although speed is rarely so significant as actual damage in that it has no effect on DoTs and reduces relative resource value (relative potency per MP or TP). I'd like to see some buffs to it as well. They may have to stem from universal mechanics changes, however (e.g. TP and/or MP ticking per GCD).
Spear runs into a similar issue where it is useful only pre-burst and even then, perfected, only really outperforms even the pre-buffed Balance if there is a particular need for those CDs to come up faster and/or if those CDs include non-damaging effects (tank CDs). The card's usability really should have a lot less to do with exactly when it's to be used as on who, comparing those benefits to extending the next card's duration.
Similarly, you could do a lot with higher percentile effectiveness, but with capped totals. Ewer at present has too small an MP bonus to affect BLM rotations except in the most annoying of ways. Were it to be more far effective, even if lasting a much shorter time, at least it'd see usability. The same obviously applies to Spire.
I don't recommend caps for everything, but if you are going to have a card effect for which the window is irrelevant (as long as you don't cap MP/TP within it), then it may as well give a relevant level of effectiveness. Or, bring back the percentile cost reductions from Ewer and Spire to some degree, giving back that sense of a window. But make it a big deal, more effective in, say, an AoE spam than would Balance and simply regenerating resources between strikes (or after having finished off the enemy that 10% faster).
I agree in theory. However, in practice, most developers fail to consider across each encounter designed how far the output gap between high skill floor/ceiling (difficult) and low skill floor/ceiling (easy) classes may tighten, or even flip, in interaction with certain mechanics. Sometimes the easy build is superior in certain fights even in the hands of an absolutely perfect player simply because it has far fewer possible pitfalls, making it relatively immune to CD waste or uptime loss, etc. It's those fights, where people who enjoy a challenge are forced to play the superior "easy mode" class or build that end up giving the idea a bad wrap.
However, personally, I'm also of the opinion that these should only be build-wide variance, not class-wide, so long as the class is the center of time and currency spent, rather than the player in general. If each challenge or task's worth of experience acquisition applied to all classes seemingly relevant to that task or challenge and systems like weekly caps and job-specific currency expenditure didn't promote focusing on one class, then I could see these individual classes as, basically, just builds, between which the player can easily swap with just a matter of getting into the swing of the new gameplay rather than requiring an additional process of leveling and/or gearing. But alas XIV does not presently work that way, and I think it would be a shame therefore if each class didn't have access to both a high and lower skill-floor/cap way of play. (E.g. WM-only or dance-less Bard, easy BotD-hold rotation, easy burn BLM, etc.)