Not agree, we don't need more homogenization.
AST smooth gameplay with the 1,5s cast time is for his use of cards (and was already there since 4.3)

I know everyone want this for WHM, but I would go for a BLM treatment.
Both were compared before as a raw powerful job. I think WHM should follow the BLM path and have more tools to deal with movement, that's it
Why not a water ability where you can do a quick dash on a line and doing damages ? Even rework the Presence of Mind to have a kinda Leylines maybe if it can please people.

SCH should function the same as before, Fairies skills independent from SCH toolkit, so we don't have a tons of oGCD to throw (and so reducing largely the use of Ruin II).
One of the idea I like from me, is having an ability upgrading Medecine into Science (instant heal) and when using it, it transforms into Steel (instant damage), and vice-versa for 15sec.
So it adds a bit more instants, gives interest to Medecine, use the lore of SCH, innovate the healer and healing gameplay (interaction between skills, rotation changes, etc).