Shumuckers are worthless.
See, I think this is canon. In Book 1 we see Gobwin Knob with a heap of smuckers and few units. So many smuckers in fact that the side can afford to spend most of it on one scroll.
Clearly Smuckers can't be used to pop more units, increase the quality of units, or speed the popping of units. Otherwise, Stanley would have done all those things as the war went badly...
If they can't be used to upgrade, how does parson upgrade at the knights in the jetstone capital to heavies, at substantial cost to the treasury?
Also, why would one expect Stanley to be smart?
Schmuckers are useful, especially if paired with a Moneymancer. That's where I disagree with the otherwise spot-on analysis of jojolagger. Imo, Turnamancy and Moneymancy share top spot as by far the most useful disciplines as presented in that version of the spell compendium.
Dirtamancy isn't too bad early on, as it has some overlap with econ-boosting spells from Moneymancy. Once the Moneymancer can accelerate production of D-class units though, it's clear who wins that magic contest.
Yeah, I'm seeing those two near the top.
Turnamancy can convert units, boost speed, boost duration, and cut production times. All good stuff.
Moneymancy adds useability to the little used schumukers, which normally just determine city level and warlords.
The others I see "up there" are Luck, Think, and Shockamancy.
Luckamancy, because rolling a 7 on a d6 is cool. Rolling a 506 on a d6 is just outrageous. (And expensive, but but +5000% to a single round of combat would let a single stack of stabbers mess up a D-class stack.)
Thinkamancy, for caster links, finesse control of units, stunning, 2 forms of manipulation, and mind reading.
And Shockamancy, because ignoring defense means flawless assassinations and Massive combat damage. Shockamancers are cannons. Just Tesla and a level 1 deals 18 hits right at the start, which can assassinate just about anything short of a level 10 warlord or a special C or D with a heavy focus on hits. With Decent Tactics and a pile of scrolls and infantry to take hits for him, a low level shockamancer could easily tear apart a larger force.