The fact I am able to point to the SCH and AST equivalents in the majority of WHM healing and DPS spells I think is a testament to how homogenised they are. We joke in our group that the choice in healer jobs are WHM with a faerie, WHM with wings or WHM with cards.

Even to a certain degree Adloquium and Regen may find themselves used in the same situation, despite having a different effect, though Adlo more frequently. I guess a testament to it is that I was playing AST the other day and halfway through a dungeon I was like "I'm in Diurnal, I thought I was in Nocturnal", although they are supposed to be different playstyles, I was able to play them identically without noticing a difference.

I think each class needs areas they're weak in, so they have to use their toolset differently. This is one of the main reasons I liked 2.0 healing, because SCH was weak where WHM was strong and vice versa, it meant I had to think or work harder to keep up with the bits WHM found easier. I liked that.