I'm almost done with my new versions of character classes for TSR. I just have the Warlock (Magic-User/Thief hybrid class) left to go. And then a few tweaks to keep certain options viable and prevent one from being the "go to" option. At least as I see it. How they end up in play will remain to be seen, as I don't know if my West Marches folks will go for another rules switch. [Plus I was just bitching about Jeremy changing the rules all the time in the weird body-horror fantasy game he's running.]
Anyway, the thing I'm kind of proud about with these rules is the modular nature I'm building into it.
A really basic game might have only humans, who can be Cleric, Fighter, Magic-User, or Thief.
A slightly more complex game might still be human-only, but add in subclasses.
Or human-only, but adding in the advanced classes.
Or adding one set of demi-humans (Euro-Tolkien, or Asian fantasy), but keeping the basic four classes.
Dial up the complexity a bit more, you get humans & demi-humans, with the four basic classes with subclasses allowed, or four basic plus the advanced classes.
[A few more tiers exist, adding in certain combinations but not others, like limited demi-humans but all classes/subclasses, or allowing some subclasses/advanced classes but not others, etc.]
Most advanced would be to allow all demi-humans, all classes and subclasses, and letting the advanced classes choose subclasses of their basic class counterparts. The big kitchen sink approach. This would be 13 races and if we count each subclass as a class of its own, we get 112 potential class combinations. Some of the advanced class options won't work too well together. The Monk (Cleric/Thief) would lose much of its monkishness if it were a Darkstalker/Outlaw instead of a unique Cleric/Acrobat, but that still might be a cool option for some people. Likewise, a Bard that's Druid/Geomancer (Wu Jen) might feel off stylistically.
I think the ideal would be to allow a select set of demi-humans (and feel free to mix Tolkein with Asian, why not have Elves and Dokkaebi but no Halflings or Kumiho?), each base class with its subclasses, and the advanced classes without subclass substitutions. But if someone came to me with a concept that called for an advanced class with variation, I'd consider it. Also, I'd encourage DMs to tweak the advanced classes to fit their campaign. If they want more Asian influence, Bards and Paladins should use the Shaman spells instead of normal Cleric spells, and Bards, Larks and Warlocks should use the Geomancer spells instead of the normal Magic-User spells.
Anyway, it's customizable and easily dialed down or dialed up in complexity/options. If I ever get this in a publishable state, I'd likely give away a "Bare Bones" PDF for free, and then charge for the more detailed version.