As a career AST, I kind of have the reverse opinion. In fact, I'm leveling CNJ and planning to main WHM for Stormblood because of how much I have that reverse opinion. The tools that AST will receive are basically things WHM kind of already had - and in several ways, WHM is still strictly superior. Gravity is just a crappy version of Holy, and now that WHM will get Thin Air WHM will be so much better at taking advantage of the Cleric Stance change. While the cards are great utility, the only thing that ever really stood out to me to make AST's healing seem amazing is how ridiculously good Nocturnal Aspected Benefic is - an opinion I've had since HW launch, mind you. In fact, I hate the SCH/AST meta because I think Nocturnal AST is infinitely more amazing and interactive than Diurnal AST.

To me, switching to WHM seems like I'm losing some utility to gain a more personal and direct impact, which I think is okay for the large majority of players, and furthermore it's okay for some of those holes to exist. The biggest hole is that AST is simply prettier, anyway.