End game raiding is the only part where intricate class balance actually matters. No, the only caster that was remotely competitive among all classes which is more important than this caster war you keep wanting to continue was SMN and only because their damage was overtuned enough to make the DRG+BRD+MCH synergy less important. Casters need to be competitive among the other classes. Instead we have our 'support' caster which has weaker support, damage, and mobility than both of the ranged physical DPS classes. A 'no utility high damage' caster that gets outclassed by the fact that its damage isn't sufficient enough to break the previously mentioned meta and a 'mild utility, mild damage' caster that again, has only broken the current end game meta because its damage was overtuned. I'm not saying the other content doesn't matter at all, it's just that it's not as relevant as far as balancing is concerned because the other content isn't rigorous enough for parties to justify not taking specific jobs.
As far as ST, AoE, and support, each class needs to have a use in each category or they have to excel only at that category enough to make a difference. Now take into account that all raid encounters are single target and the AoE job is no longer usable there because why bother. The support and ST class now have to vie for a spot in which either the support has to have enough useful support to make up for the fact that its ST dps is going to be lower. There should be a justifiable reason to take any job to end game raids at any point along progression. And for the most part if a job is performing well in the most serious end game content it will perform well in the less taxing content.
Basically the only reason you would take any caster at this point is because they have Raise, one of which has a disproportionate amount of access to it and one that has the same as healers do, now throw in the fact that one does significantly more damage than the other and gets gimped far less for using it. And then Black Mage doesn't have Raise and not enough DPS to justify its stark lack of utility.