In designing a new compulsion spell am not sure whether to follow the cleric tree or the bard/wizard/sorceror tree in regard to spell levels and other rules/effects.
On the cleric side, we have command…
Level: Clr 1
Components: V
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One living creature
Duration: 1 round
You give the subject a single command, which it obeys to the best of its ability at its earliest opportunity. You may select from (Approach, drop, fall, flee or halt)
…and greater command.
Level: Clr 5
Targets: One creature/level, no two of which can be more than 30 ft. apart
Duration: 1 round/level
On the bard/sorc/wiz side we have suggestion…
Level: Brd 2, Sor/Wiz 3
Components: V, M
Casting Time: 1 standard action
Range: Close
Target: One living creature
Duration: 1 hour/level or until completed
You influence the actions of the target creature by suggesting a course of activity (limited to a sentence or two). The suggestion must be worded in such a manner as to make the activity sound reasonable. Asking the creature to do some obviously harmful act automatically negates the effect of the spell.
…and dominate person.
Level: Brd 4, Sor/Wiz 5
Components: V, S
Casting Time: 1 round
Range: Close
Target: One humanoid
Duration: One day/level
You can control the actions of any humanoid creature through a telepathic link that you establish with the subject’s mind.
If the spell will be available for players, how does one decide to which type of caster it will go to? It appears to me that arcanists have the upper hand in enchantment… Why is the power of (insert deity here) not very compelling?
Best Answer
The best way to judge what classes should have access to a spell is to compare it to the kind of spells those classes already have.
Wizard and Sorcerer compulsions tend to be forceful in method and drastic in effect: The examples you gave describe subverting the victim's normal mental process by forcibly inserting a foreign thought, and blatantly stealing control of the victim's mind.
Clerical spells, on the other hand, tend to use more straightforward methods of achieving their ends, and often express the role of clerics as spiritual leaders: Thus, the spells that allow them to speak with authority and be obeyed.
As for why the power of Power X isn't compelling... Well, if you look at the ecology of gods as described in, for example, the Planescape setting, belief is the food of the gods - without it, they lose strength and eventually starve to death, or at least enter a state that is for most practical purposes equivalent to death. A follower who only vaguely follows their patron deity's teachings is still more faithful, and therefore more valuable, than an unbeliever magically compelled to serve. Of course, individual gods might have a thing for magical compulsion, but that's not enough for something to get included in the standard priesthood package.
Oh, and like mxyzplk suggests, there's more game design-y reasons for it, too: if Clerics were good at all forms of magic, they'd be far superior to wizards, even enchanters - and playing an enchanter would be much less interesting.