As was said before, and is my personal opinion as well, is that SCH have more in the way of proactive rather than reactive.

SCH have to be able to see a few seconds more than a whm and act accordingly. and a stoneskin + adlo combination is way more potent as SS 18% since they stack.

And also i like that people assume we can have unlimited mana, but thats for when you are not using any lustrate or sacred soil at all. even if you drop sacred soil and you use shadowflare, still lustrate is going to be needed, especially if the party is struggling around.

Even with 6 of them (cast before entering, cd off) you might find yourself lacking in mana or even dropping bellow 25% in some cases. go on level, with an on level party in Stone Vigil. its going to challenge everything you are as a sch