My issue with AST currently is that "fine" isn't good enough. Why would I consider playing a Job with tools that are, for the most part, merely adequate when I can play a true powerhouse healer like WHM or SCH?

Being passable at everything while excelling at nothing is a death sentence for a healer Job. There are three to choose from and high expectations for the role they occupy, at least when it comes to end game play. No one will want the healer with the most limited burst healing, the fewest healing CDs, the mediocre sustained DPS, potentially the worst MP-efficiency, and the RNG-heavy utility options.

I don't believe that waiting until we overgear everything to the point where the weaknesses cease to be as noticeable is a fair balancing solution.