Trippy wrote: People cite Pendragon a lot, but they did have a published magic system (however uncinematic and time-consuming it was!), that could at least be referenced for those who expressed an interest.
Yes, and it's something Greg Stafford quickly got rid of in later editions, regretting it's addition to the game. Pendragon 5/5.1 only has magic as a GM device/plot driver not as a Character Class and it's stronger for it.
Personally, I don't see Gandalf as a PC; he's more of an accompanying NPC and many of the other references to wizards and users of magic beyond the Istari and the stuff available to elves and dwarves are invariably evil or tied to a greater enemy. I therefore don't see why there'd be any need to have one as a PC culture, beyond what we already get as Virtues for elves, dwarves, etc.
I agree with previous posters that adding a spell-casting culture would send the message that these are readily available and common to the world. That's not something that is true of the literature at all. If they were introduced then it's highly likely that published adventures would start to include elements, plot points, etc relating to them; this would therefore impact negatively on many players and gaming groups that didn't want to see such things.
So, no magic-users thanks. There's enough magic within the game already.