I was reading Philotomy's OD&D Musings, specifically the part dealing with Vancian magic, and was wondering how to rectify it with the type of magic we see in the Conan stories by REH. We never really see anyone "cast a spell" in those tales, although magic is frequently used. It's almost always a lengthy ritual of sorts, or through a magic item. So...does anything actually need to be changed?
Well, I started typing up this post in some effort to outline a new set of rules or whatever, but what's the point? D&D already assumes spell-casters must spend a certain length of time to memorize a spell, even if they can then cast that spell "instantly" at a later time. Spells like Identify specifically outline a ritual of sorts; you can't just cast ID whenever you wish, even if it is memorized. The mechanism already exists for duplicating ritual magic, but no one ever plays that way. Who's to say a wizard cannot simply choose to not fill all his spell slots and memorize them when necessary? Essentially that's all the sorcerers in Conan do...all the DM needs is a house rule that stipulates spells must be cast immediately after memorization. That's it. Ritual magic is done.
Now, this makes the magic-user even more vulnerable, and almost helpless at 1st level. So what? If you're striving to duplicate a true Swords-and-Sorcery feel, a sorcerer is going to fall to a sword swing rather quickly, he won't be throwing fireballs or lightning bolts. This actually brings up a rather interesting issue: if a magic-user cannot memorize a bunch of flashbang spells, what does he do for defense? Plans even more carefully, of course. There will probably be MUCH more emphasis on summoning spells, illusions, invisibility, etc. Indirect ways of dealing with problems, on the wizard's own terms. When he does need to directly confront an unruly barbarian, break out the wand or staff and start the fireworks. It's interesting that this is pretty much what Thoth-Amon does. Nearly helpless without his magic ring, he is nigh invulnerable with it. When he wants to dispatch Ascalante in The Phoenix on the Sword he certainly doesn't show up with a wand of magic missiles and start firing like a maniac. Instead he sends a summoned demon to do the dirty work. And why not? High chance of success, extremely low chance of getting hurt himself.
Even though stylizing D&D magic to more closely resemble the type we see in S&S is fairly simple, I don't think I'd be convinced as a player to accept playing this way unless I got something in return. Perhaps Sleep and Magic Missile and Feather Fall and a few other spells could be instantaneous. Or the DM could give a magic item with limited charges (1 or 2) that are reusable every day. I suppose allowing summoning spells to last much longer (perhaps upwards of days or weeks) would get even closer to the source and give a legit reason for playing a wizard. At any rate, the Vancian magic system works JUST FINE in the sense it is intended. With some minor variation I think it can adequately model a wide variety of literary sources.