So my sweetheart and I have been discussing the issue of scrolls and their casting requirements lately. The trigger was that my group (a Sorceress/Oracle and a Rogue/Cleric) found some scrolls, one of them Dispel Magic, which I could actually need at this point. When I found the whole batch, we figured it wouldn't make sense for Dispel Magic to be the only arcane scroll in a batch of Cleric spells, so we agreed on it being divine too.
Now, my Sorceress is usually the one casting spells from scrolls, but I realised that, hey, if the scroll was written by a Cleric, wouldn't I need Wisdom to cast it?
The RAW don't seem to give a definite (and satisfying) answer to the scroll problem (who scribed it, which stat is needed, which CL, etc.) and after some back and forth, I came up with a solution I like (I still don't know whether he will houserule it the same way for the campaign he's running for me, but I definitely will in my campaign):
Back in NWN, scrolls usually came with all possible caster classes and spell levels on them. Now in that case, I will treat each scroll (either bought or found) as if it had each possible caster class and spell level on it too (more to pricing later), and whoever tries to cast that spell can choose which casting class he wants to use.
For example, my Sorceress could choose to cast Dispel Magic as a Sorcerer spell with the appropriate CL 6 and the casting stat Charisma, while my Rogue/Cleric could choose to cast the same scroll as a Cleric spell with CL 5 and Wisdom as casting stat.
Now, if a Wizard wanted to cast a Bard spell, for example, he would need UMD to use the scroll since the spell wasn't on his own spell list, and--if necessary--he would need a second UMD check to emulate the appropriate ability score for the casting stat (Charisma). He would NOT be able to use Intelligence as casting stat, since Bards use Charisma!
Pricing:
If scrolls list all possible caster classes and spell levels, that also means that most scrolls could be cast at different CL (sometimes even as different spell levels).
To stay with Dispel Magic as an example:
Cleric 3 / Oracle 3 / Wizard 3 / Sorcerer 3 / Bard 3 / Paladin 3 / Druid 4
We have three spontaneous caster classes with basically CL +1 (6) in here (Bard, Oracle, Sorcerer), two casters at normal CL 5 (Wizard, Cleric), the Paladin at CL 10, and the Druid at normal CL 7 (4th lv spell!). To determine the spell level and CL for the price, add together all CL (6+6+6+5+5+10+7) and divide it by the number of classes (45/7=~6.5). Then do the same with the spell levels (3+3+3+3+3+3+4=22; 22/7=~3). To make things a little easier, round to half levels.
The price for Dispel Magic would be 6.5x3x25gp=487.5gp
I know that pricing gets a little more complicated with these houserules, but honestly, think about this: If a Druid found a divine Dispel Magic scroll (usually worth 375gp=as scribed by Cleric), would he cast it as 3rd or 4th level spell? If he'd cast it as 3rd level spell, why? It's not on his spell list at that level.... If he'd cast it as a 4th level spell, he'd get the benefits of a 4th level spell for the price of a 3rd level spell. Or, let's get more extreme: If a Paladin cast Dispel Magic from this scroll, would he use his own minimum CL (10!!!), or the Cleric's? If the Cleric's, why? And if he cast it at the Cleric's CL, would he have to use the Cleric's casting stat too?
The point I'm trying to make here is that while my pricing might seem too complicated, the RAW are actually open to a lot more confusion and arguments.
If we just went with the assumption that each scroll is either scribed by a Cleric (divine) or Wizard (arcane), then, for consistency's sake, characters would also need to use either Wisdom (Cleric) or Intelligence (Wizard) as relevant casting stat, which would basically screw Sorcerers, Bards, Paladins, and Oracles (all of which use Charisma).
Now, just for the sake of completion, in my homebrew scrolls can be specifically written for just one class (e.g. a Wizard scribing scrolls for his own use) at the normal price specified for that class. However, a Sorcerer could not cast a Wizard's scroll without UMD and Intelligence.
Okay, and now roast me ;)
your crazy gnome lady from next door
Almost. The first UMD check would be to use the scroll (it's 20 + CL), the second UMD check to emulate the corresponding stat (if your Ninja doesn't already have a high enough stat).
Suzaku, then would you theoretically allow a 5th level Sorcerer to cast a 3rd level spell without a CL check, off Charisma? Or, more extreme, a 5th level Paladin, although he wouldn't get access to 3rd level spells until 10th level?
We run similar rules in terms of caster class. If it's on the spell list, you can cast the scroll regardless of its scriber. It's nice to be able to say "spell X is on class Y's spell list, so I'm going to cast it as such". However, we still stick to normal scroll caster level and pricing rules.
Suzaku, then would you theoretically allow a 5th level Sorcerer to cast a 3rd level spell without a CL check, off Charisma?
Don't see a problem with it personally.