The Colour of Magic was a great article and is one of the few that I often see references to on Classic-D&D related sites even now, roughly 15 years after it was published. The core concept was that the relatively small spell lists in (RC-era) D&D meant that everyone who had ever read the books would know all the spells and as you know, familiarity breed contempt. Joyce's solution to this was simple: Still allow the same game effects (mechanically) but allow different magic users to describe their spells differently. For example:
Grimfang is a 3rd-level goblin magic-user, the shaman of a small tribe that uses spiders of varying sizes as guards, mounts, and totem animals. All her spells have an arachnid theme.
First level: Shield (Chitin). Grimfang's skin turns into tough, articulated chitin for the duration of the spell, giving her a spider-like appearance.
Sleep (Spiderbite). Range: Nil. Duration: Special. Grimfang can inject sleep-inducing poison by biting. This requires a roll to hit in combat. She can put 2d8 hit dice worth of creatures to sleep for 4-16 turns (determine the duration secretly when the spell is cast). Any creature bitten that has over 4 + 1 hit dice, or more hit dice than Grimfang has hit dice worth of poison remaining, is unaffected (the magic-user still loses the relevant hit dice worth of poison, however). ... The victim of this spell is affected as per the standard version of this spell: sleep for 4-16 turns, no saving throw.
Second level: Web. Standard spell.
Get the idea? You could take any concept (fire magic, ice magic, animal magic, ghost magic or anything you could think of) and reimagine the descriptions of any spell to match that concept. Imagine this: the party is coming up on a single magic-user. He holds his hands out and balls of flame form in his hands. They panic. They aren't tough enough to handle fireballs! But is it a fireball, or is he just a bog-standard fire mage preparing to let off a small volley of magic missiles (that just happen to have a very similar appearance to the more deadly fireball)?
There is a secondary part to the article, one which is even more related to the "mystique" of the magic user.
Xeno the Enchanter can conjure a fireball by waving his arms about, but he cannot light his pipe by snapping his fingers.This is important. A magic user is a breed apart, messing about with the very building blocks of nature. He should be able to do slightly fey things just because. So Joyce suggests that they can. Just little things, like lighting a pipe or a fire or swatting a bug out the air. The article does make it clear that allowing magic users to do these little "extras" shouldn't allow them to do things that they couldn't otherwise do without magic. But in the case of the mysterious wizards how they do it is more important than what they do.
Think of Gandalf and his smoke rings, or even his fireworks. Even Raistlin managed this sort of stuff (if I'm remembering rightly, Dragonlance has been long neglected around here).
On a related issue, James Maliszewski (of Grognardia fame) has posted a list of Minor Magical Effects related to currently memorised spells.
This is a slightly more potent version of Joyce's "bonus effects", but one that fits in even more closely with the Vancian roots of the D&D magic system. (As an aside, I have only read Jack Vance's Dying Earth very recently but I can tell you it was a serious "aha!" moment when it came to understanding what Gygax and Arneson did when it came to spells).
I'm not sure where I read it, but someone suggested that Vancian spells have an almost sentient nature to them. Your magic user spends a great deal of time and effort into cramming them into their brains and they are bursting to get out again. Maliszewski's idea fits in beautifully with this concept. With the spells packed inside his head, the magic-user would just be radiating the very nature of that spell, almost struggling to hold onto it. It seems appropriate that the effect should be almost visible.
Note that the Minor Magical Effects are related specifically to currently-memorised spells, rather than just general-concept bonuses like the Colour of Magic suggested. I'm not sure that both systems would work that well together. Perhaps if you created a concept-mage (a la Colour of Magic) many of the Minor Magical Effects would be similar for all the concept spells. For example, the fire mage would have a fire-Magic Missile, a fireball, a Wall of Fire, a fire Shield and probably a lot more memorised at any one time and so he could probably always light his pipe by snapping his fingers.
Other than sharing two articles I found very interesting, I don't think I'm really suggesting any particular course of action here. I'm not really even doing much along these lines in my own games (such that they are). Hope they might just get some thoughts flowing (for myself and others).
By the way, issue 200 of Dragon is one of my favourites. Not least because I had a letter published in it, leading to an interesting couple of years of play-by-mail games (but that's an idea for yet another post).