It's still a rough draft, but it sould be enough to understand what I'm striving at; so here it is for anyone to dissect:
- spellcasting is spontaneous for all classes, but you have no limits on the number of spells you may know or on the number of spells you may cast in a day
- the wizard and sorcerer classes become the same, mechanically equivalent, arcane spellcasting class (with wizard progression and bonus feats)
- divine casters don't have access to all the spells on their spell list, they have to learn them like arcane casters do
- the 1st level of a spellcasting class (not PrC) grants you knowledge of all its level 0 spells and of a number of 1st level spells equal to 4 plus the relevant spellcasting stat bonus
- the 1st level of a spellcasting class (not PrC) also grants you a set of "basic" metamagic feats known (as described in the next post)
- each level past the first in a spellcasting class nets you two free spells known of a level not higher than your Caster Level / 2, rounded up
- you can research spells of any given level, provided you have enough time and resources
- spellbooks are used exclusively to research and learn spells, while scrolls can't be used to learn spells at all
- to successfully cast a spell you must beat a Spellcraft DC of at least 12 + Spell Level * 2.5 (though ad hoc DCs may be worked out for some spells);
- taking 10 to cast a spell is allowed (but the usual limitations apply)
- to learn a researched spell you must succeed in a Spellcraft check, the DC is the same as that needed to cast the spell
- spells don't scale with level or skill, they are improved via feats
- applying metamagic feats to a spell generally doesn't increase the casting time (unless the feat states otherwise)
- applying metamagic feats to a spell raises the Spellcraft DC by twice the spell slot adjustment
- the amount by which you fail (or make) your "Spellcraft Check" (SC) triggers a different status:
SC <= (DC -10) : you become exhausted
(DC -10) < SC < (DC +10) : you become fatigued
SC >= (DC +10) : your current status doesn't change - some feats lower the DC of the spell being cast, increasing the casting time
- while exhausted you can't cast spells; 1 round after your last casting you become fatigued
- while fatigued you can cast spells; 1 round after your last casting you fully recover
- if you're fatigued, something that would make you fatigued makes you exhausted
- if you become exhausted twice in a 10-round span, it will take you 10 rounds to become fatigued and then another 10 rounds to fully recover; a restoration spell drops the recovery time back to normal
- SR is completely out of the equation; in its place you get invulnerability to all spells of a given level and lower (à la 3e Rakshasa) and/or invulnerability to spells with a specific descriptor
- some monsters may list a few spells that bypass their invulnerability
- some feats raise the actual level of the spell they're applied to
- Last, but not least, Spellcraft will be a Class Skill only for primary spellcasters