I have a few comments on the Demagogue spell and I would like to discuss them, so here goes.
The spell in question:
Demagogue
Enchantment (Compulsion) [Mind-Affecting]
Caster level: Arcane 3
Regency: 3 RP/province
Casting Time: One free action (1 day)
Range: Long
Area: 1 province +1 province/2 caster levels after 5th
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No
Description: The wizard can change the loyalty of the people inhabiting a province drastically. He can either make the province ruled loved or hated, changing the prosperity of the area equivalently.
Spell Effect: All provinces affected have a +2 bonus or –2 penalty that turn. The caster may choose to have different effects in different provinces.
The duration needs to be changed to 1 Turn instead of Instant - Bjørn, Jon, and I agreed on this. It's a little misleading to call it instant - as that implies that the magic is only active for a very short time, then things run their natural course. THat led me to believe that Prosperity increase was as permanent as damage or healing - until the new damage is dealt or you are healed, the effect remains. Essentially, the equivalent of Agitating succesfully twice in each affected province... somewhat overpower on second thought, but hey, I was feeling optimistic.
Anyway, the spell now only last for the turn in which it is cast and I think this makes it a little too weak compared to other spells with the same effect and/or level. I'm comparing it to Bless the Holy Land:
Bless the Holy Land
Transmutation
Level: Divine 1
Components: 1 GB/target province
Regency: 1 RP/target province + special
Casting Time: One free action (1 day)
Area: 1 province + 1 province/2 caster levels beyond minimum requirement
Range: Long
Duration: 1 domain turn
Saving Throw: None
Spell Resistance: No
Description: The spell is usually cast by the principal temple in each province, and most relatively civilized provinces tend to benefit from it on a regular basis. It represents the clergy performing a wide variety of ceremonies and blessings throughout the province. The populace feels invigorated and happy, making the province more productive.
Spell Effect: Target province gets a +1 morale bonus to province level (except for the purpose of collecting regency) and a +1 prosperity modifier. Bless the Holy Land counters Blight the Accursed Land.
The caster must pay an additional number of RPs per province equal to the difference in target province level and his holding level. Example: Casting Bless the Holy Land in a province (6), where the caster has a temple (4), costs an additional 6-4 = 2 RPs
Effect-wise these spells are pretty much equal. Getting +2 Prosperity is pretty much the same as getting +1 prosperity and +1 province level. No biggie. The reason the Arcane spell must be higher level to give the equavalent benifit is that Blessing/Boosting provinces is a Cleric specialty - of course it should be easier for them.
However, given that the Demagogue spell is 2 levels higher, I think it ends up being a little weak... especially compared to other 3rd level arcane spells like: SUmmon Army III, Winter's Long Fingers, Mass Destruction, and Hidden Army. It's easiest to compare it to Winter's Long Fingers - the spells are similar in effect.
Winter's Long Fingers give the -2 Prosperity of Demagogue as well as some other effects (-25% income, penalty for army movement and foraging). It also has a massive duration of 1 year. Comparing Demagogue with that one and Bless the Holy Land, it seems a little on the weak side.
I suggest adding a duration slightly longer to Demagogue, perhaps 1 Domain Turn / 3 caster levels. That would make it last 2 Turns for a 6th level Wizard or Sorcerer, 3 Turns for for a level 9 and so on. Probably a maximum duration of 1 year. Does this sound reasonable?
I should also note that there is a bit of self interest in this. My character has learnt this spell - I mistook the duration, but do not feel especially nerfed... it's a useful spell. I still think it's a little lacking compared to other spells of the same level and effect.