Based on a G+ conversation, I had a few thoughts about how magic-users acquire spells. The method that seems most commonly used is the following:
- Several starting spells (often randomly determined)
- A free spell when gaining a level (either chosen or rolled)
- Spells may be copied from spell books (perhaps at small cost)
- Spells may be copied from scrolls (which uses up the scroll)
- New spells may be researched (at great cost, often only at higher level)
- There might be an intelligence-based % chance to know roll (AD&D)
Taken together, these rules have some consequences, especially if rule 6 (% chance to know) is not enforced. Specifically, given that it is rational to share knowledge between party members, magic-user spell lists often converge as players trade spells. Further, magic-user spell lists grow without bound. The process of spell accumulation is fun, admittedly, but if you enjoy bounded power levels, such accumulation might be suboptimal.
If I were starting a new game of TSR D&D (or simulacra), instead I might do something like the following.
- 3 random spells to begin with
- 1 random spell per level gained
- No spell books
- The only mode of scroll use is one-shot casting
I would also divide the spells into schools and allow specialists, which would draw their random spells only from the chosen school. Specialists would also gain one extra spell slot to make up for the loss of versatility and represent their focus. Thus, a player that definitely wanted to play an offensive magic-user could opt for an evoker, and be guaranteed to only get evocation spells, at the cost of generality.
This would help keep power levels more controlled while still supporting my favorite aspects of the magic-user class (creativity, preparation, being able to bust out a big nuke solution every once in a while). Magic-users could still have access to an arbitrary number of spells through the use of scrolls, but scroll use needs to be more carefully considered since scrolls are nonrenewable resources. It would also encourage more emergent character development as not every magic-user would be able to cast sleep and fireball (to be fair, that is also addressed by % chance to know spell rules, but those rules have other issues, such as increasing the importance of the intelligence score).
This will obviously not work well for players that want more control over the development of their character. It is not intended to be a panacea though, and I think it would be satisfying for players that enjoy the process of character emerging from the juxtaposition of randomly determined characteristics and events during play.