The alternative spell-designing system for this campaign based upon spellseeds & analogous mechanics has ballooned into unwieldy proportions- thanks for the advice though!
As an alternative to having the campaign effects of the ELE (the nearly universal destruction of formalized schools, spellbooks and scrolls) be merely window dressing, though, I came up with this:
When a spellcaster wants to learn a spell, instead of merely picking the spell, the PC must make a Spellcraft check to memorize it. If he fails, he cannot learn that spell until he gains another level, indicating that the spell the PC is "researching" may not be within his grasp for a variety of reasons- his research may be flawed, the copy of the spell may be a forgery, or he may have made a simple transpositional error... The Spellcraft check's DC is calculated thus:
DC = 15 + (3/spell level (PHB spells)* - 1d4 (Specialist's school) + 3d4 (Opposing School)
A Spellcraft check roll of a natural 20 is NOT an automatic success, however. If the DC to learn the spell is greater than the spellcaster can possibly roll, he may still succeed at learning the spell if he rolls a natural 20 followed by a second roll of a natural 15 or better.
Spellcasters with limited spell lists treat spells not on their PHB (or other publication's) class list as if they were from an Opposing School. A spellcaster may only prepare & cast 1 "Opposing School" spell per level per day, and may not apply any Metamagic effects to those spells, even if the effects come from a device or other outside source. Example: a 20th level Diviner whose Opposing School is Necromancy may potentially cast 10 Necromancy spells in a day- one 0 level cantrip, a 1st level spell, etc., up to 9th level. A bard, with only 6 levels of spells, could only cast 6 such spells.
* If the spell is from a source other than the PHB, it is a "Rare & Difficult" spell to learn. Thus, instead of being 3/spell level, substitute the value 5/Spell Level. Exception: if the spell is on a class' core spell list (such as Complete Arcane Spells for a Warmage), use the PHB spell value.
The main effects as I see them:
1) The ELE's effects on printed spells and arcane knowledge will have actual game effects.
2) PC spell lists will be more varied.
3) Specialist Mages and other arcane spellcasters with limited lists will be a bit more flexible.
Thoughts?