Rethinking Sorcerers

I'm thinking of changing the rules for both elves and sorcerers. Keep the rules as they are for spells known, but change the spellcasting method. Why can sorcerers only cast so many per day? I'm thinking of changing it from spell 'casting' to more of a spell like ability. Whenever a spell is cast it fatigues the caster in some way, maybe spell level increases the fatigue potential.

Going off of the rules I already have for casting those 'extra' spells; every spell requires a saving throw against spells to be cast with a penalty equal to the spell level. Maybe the INT modifier, or whatever ability score being associated with sorcery, allows the caster to not have to make this check for spell levels equal to the modifier. Also rolls that are equal to the saving throw would result in some wild magic effect, maybe reuse wild magic effects from 3e or 5e. A failure just has the spell fizzle out, and a success has the spell work normally. The hp penalty, or maybe some other fatiguing effect, would apply to every spell cast whether successful or not. So the sorcerer would be limited to spells per day not by an arbitrary number, since they no longer have to 'memorize' them. but by their hp. HP damage could also be tied to spell level.

I'm also thinking making the sorcerer have less spells known than elves. Maybe have sorcerers with an innate number of known spells determined at the beginning of character creation. This could also apply to elves. Elves are naturally born with certain spell like abilities, and some can gain more spells through study and meditation. The standard elf would be more like a ranger, a fighter with a few magic abilities. The standard elf class could still exist following the standard spell progression, but these would be the elves who pursued the study of magic. I also want to update the elven, and sorcerer, spell list to differentiate it more from the wizard. maybe look at some of the spells in the Alfheim gazetteer.

I'm also looking at ways to revamp the spellcasting methods of the standard magic-user to make it more vancian/in line with the fiction. A post about that should be coming soon.