Honestly I leveled AST (in Noct mode as much as posdible) immediately after SCH was capped, and am now leveling WHM, and the fluid simplicity of WHM is making me gleeful.

If it's the fact you feel underpowered as SCH, then WHM make be the way to go from the big bursts, but AST isn't lacking in that area. Really I think you should look at AST's card system and decide if balancing that on top of healing and weaving DPS looks to encumbering. (AST having a mitigation stance is nice, too.)

WHM utility comes more from the burst heals leading to more raw DPS uptime. It's kinda like SAM in that sense, though not as extreme.