I rank /sch as more my support subjob.
I really like the idea of /sch. The job comes with sublimation, light arts, stoneskin, and aquaveil. The stratagems are great too (fast cast stoneskin go!). You do gain -na spells though, which is huge in and of itself (but that's what remedy ointments are for...).
It sounds like a good sub until you compare to what you lose with /rdm. Primarily ice spikes, barspells, and eventually haste- key spells for soloing, though the barspells are less important if what you fight doesn't use magic spells/tp moves.
I found the overall benefits of sch to be more group oriented though. If I was asked to main heal on PLD, /sch would be my first choice. High mp efficiency combined with stoneskinga and a self-refresh puts it ahead of whm(barspells, haste) and rdm(mostly self-casting spells).
There's also /dnc, but since I don't like /dnc, I'll just skip that option.
If you're talking in a party situation on something that's actually strong, I go /sam or /nin. None of the /sch spells/abilities seem all that useful unless I don't have a healer.
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