Also, on the point of "1.5s cast times being an improvement", its the laziest solution to a problem SE introduced themselves in SHB. Scholar, despite having many oGCD abilities, had 2 dots with instant casts and could execute fairy abilities whilst casting. WHM's primary dot was 18s, providing more weave space for their few oGCDs and clipping occasionally was less punishing for casual players. AST was unique in having a fast cast Malefic (in later SB patches), allowing them to weave their cards and plethora of oGCDs. Reducing all cast times to 1.5s and giving a trait unique to AST to all healers, despite making the jobs much better in the current design space, just makes jobs even more boring since there's even less of a reason to use movement tools.