Just addressing the bolded part: the sad thing is, is that AST has taken over WHM as the prog healer. Especially in this tier where ASTs can pop Lightspeed during periods of heavy movement (e.g., o12s) and heal the party (or use Star), where as WHM struggles with any healing if movement involves. Meanwhile, all WHM had for heavy healing really was Cure III, which is less useful during things like Hello World because the party spends the majority of the time not being stacked up for it. ASTs struggle a tad more with MP compared to WHM, but they have tools at their disposal that WHM simply does not. Upload-wise, AST is dominating WHM in Savage.
The Assize change will give a bit more DPS. But between the clipping WHMs have when trying to weave in oGCDs like Assize, Tetra, Bene, or Divine Bension and early clipping of Aero II just to have an opportunity to weave, I don’t know how much they actually gained in the long run. Everyone saw what happened to AST when they reduced the cast time of Malefic III to 1.5s, and how their damage just shot up because they were no longer clipping their GCD every time they had to do card things.
Honestly, I think they should have given WHM the AST treatment of 1.5s cast times on Stone IV—to allow its personal DPS to increase and deal higher damage (for a healer) to offset the fact that it doesn’t have any answer to Balance. But, it somewhat doesn’t surprise me that they didn’t even do that.
And, sadly, it still may not have been enough. But I think it would have been better than the Assize change. Because now you’ll be clipping either your GCD or your Aero II DoT early every 45secs as opposed to 60secs.