Tim at Gothridge Manor dropped an idea yesterday about using spell components as enhancers to magic, not requirements. I'm so taken with this, if he'd written about it a week earlier I might have included it in my house rule anthology.
When I asked for what might need house ruling there was some talk of magic in general but it didn't trigger in my mind a memory of material components. I love them-- eye of newt, toe of frog-- what could be more magical. And yet from my experience 1e's material component requirements for casting spells were largely handwaved, you were either assumed to have them or maybe paid a lump sum to represent the value of the components. (Maybe anything that was largely ignored in 1e, and seems worthy of saving, would be a great place to look for possible elegant solutions).
Anyway, with Tim's suggestion spell and potions work as normal. If you add components they work better. This is nice because 1) everything works as a baseline; don't want to mess with components, you don't need to 2) flavor can be easily injected without complicating things-- I'm thinking small bonuses or additional damage, range etc. 3) players get to decide when to do that: have a very important charm person attempt coming up, better gather some materials 4) players can also get involved creatively in working out what materials might work 5) this makes them interact with your world more, maybe even causing hooks as they seek out certain rare things. That's a lot of good stuff for very little in system price.
I'm going to try to re-cast it a little in my own words. This may be the only time I've wanted to add complexity to a house rule, but I think there is room here for a little more flavor without complicating things too much. The thing about material components is what exactly makes any one material more likely to make a spell work better. This is where we can get the flavor of sympathy, contagion and correspondences into our games.
These ideas can overlap a little but sympathy is when the material is like the effect you are trying to get, so, little wooden wings might help a fly spell, the sand used for sleep is reminiscent of the Sandman, etc. Contagion is when the item is infused with what you want to affect, traditionally you collected fingernails and hair clippings to cast a spell on someone, the true name of a person etc. The two can overlap when you start thinking, does salamander skin help a fire spell for one reason or the other, or both? I think I would artificially simplify these concepts so that contagion meant only the thing you were wanting to affect has touched, owned, loved the component. I'd say salamander skin helps in a sympathetic way; you can make fire better because the salamander skin is very fire-like, besides you're trying to make fire not cast a spell on a salamander.
Correspondences are more systematic, even arbitrary relationships. Take a look at the tables in Fantasy Wargaming if you have it. Certain numbers, star signs, gems, and woods are better suited for certain effects. The material component might be a beech wand set with seven rubies. None of these give much hint to their sympathetic effects, but if you are an initiate into the arcana you would know what the wand would be best suited for.
So, having explored that a little, here's how I might explain to a player:
"You can cast spells as written, but sacrificing certain items will make your magic more likely to take effect and more powerful. Using the Principle of Contagion will make your spells more likely to affect a target, the Principle of Sympathy will make your spells more powerful, and using the System of Correspondences will allow you to choose either of those results."
As a DM I'm fine with making rulings on the fly, or negotiating this with players, but I want to do a little thinking ahead of time about how I might handle things. Below is the order I might apply effects, so if a player has used multiple components, rather than giving a target a -7 to save I might click over and do all these things before coming back around:
Principle of Contagion:
names, things owned, parts of target = minus to target save > + to damage > + to range > + to duration
Principle of Sympathy
items that are similar in nature to the desired effect = + to damage > + to aof > + to # affected > + to range > + duration
These numbers, symbols, items are traditionally associated with the desired effect = player chooses which effect to enhance
For all materials, the harder it is to obtain the more effective. Ubiquitous items may have no effect. Basically, more expensive is better. But difficult to obtain comes into play here to: for contagion, finger nail clippings would be more powerful than knowing a target's name.
I want to make a nice, simple chart of correspondences to give to players. I suppose you could also dish that info out as they climb in levels and are entered into the mysteries of their art, too. Or let them find books with this info as treasure. Lots of possibilities. Thanks Tim!