...What the hell are you talking about? From the career WHM I've spoken to on the matter of subjob, subbing SCH is the hands down best choice for curing, if you care about the maximizing your curing with -10% MP off cost with light arts, not counting using stratagems. Using -na spells comes out over Divine Veil (enhancement giving -na spells aoe effect when randomly activated) because you can choose it. It does beat out RDM from what I'm told when expanding the role of WHM.

RDM isn't a bad choice either. It's simplistic, familiar, and it gets the job done. But SCH is already in place as a number one prime pick for career WHM.

You want to complain about uselessness of a subjob, go try to use /smn again. Larger MP pools and auto refresh was the only thing it brought to the table but now most mage jobs have an abundance of MP, refresh gear and/or have better, aka useful, subjobs to use.

...and I started to ramble. tl;dr
You don't know what you're talking about, SCH is fine as a subjob with what it offers.