Swords and Sorcery Specific House Rules
spelljacking-like rules for priests and wizards are in play. (costs can involve stats, HP, and save vs polymorph)
altered interpretation of chance to learn spell mechanics: you don't have to wait til next level.
- research opportunities can grant extra attempts, AND there are... ways... to get bonuses before and after you roll.
clerics don't get spells from omnipresent olympians. Shamans negotiate pacts with each spell-spirit (closer to shadowrun than Vance.)
Wizards: there's no "read magic" as there's nothing universally true about the collection of stolen/cobbled rituals they call spells -- one who makes serious use of spirit pacts is called a Sorcerer, like Moorcock's Erekose.
So the narrative impact trickles down to rules changes in spellbook management, like: good news: if you fail to learn a spell, you can't reattempt it til you gain a level have a narratively significant reason to roll again, like having leveled up or found a similar spell that you can scavenge novel somatics from. good news: like hackmaster spell jacking, the official "spells per day" is only the safe and sane limit on such. Also, you can ritual cast above your paygrade.
bad news: Wizards are cagey about giving away copies of their spellbook because spells wear out. (You might refurbish a failing levitate spell by altering your personal copy to include the fractals you've discovered in the feathers of a Roc as part of your research into why they don't fall out of the sky.) But wear and tear won't show up unless group interest turns this into a campaign. Unless somebody casts Wish.