I'm sure it's been mentioned in over 470 pages of forum, (and speaking as an AST main who keeps getting the rug pulled from under their feet every expansion) I want to feel needed in combat. The class trinity works because the core fantasy of each role is "You wouldnt be able to complete this without me" and that's simply been forgotten, or perhaps willfully ignored? AST in particular, has had several fun side mechanics beyond "Health bar go up!" and "Health bar go down!" over the years, which were really what was keeping the role fun for me.

Maybe we could solve this by forcing Yoshi-P to make John Finalfantasy into a healer for the poster job for 7.0.