The Shaman said:
I can see this as well.
Dog House Rules' Sidewinder: Recoiled, Adamant's pulp Modern AdCs (Thrilling Tales?), and RPGObjects' Blood and Guts all take this approach, of AdCs that are consistent with one another to represent a genre.
IMX AdCs created this way to represent genre types are usually well-balanced relative to one another, but may be out-of-balance compared to the core classes. One of the things that I appreciate about the MPC is that the AdCs mesh pretty seamlessly with the existing core AdCs.
As far as more genre treatments like those mentioned above, I could see expanding the options. As far as generic AdCs to expand on the core rules, I'm a bit leary of the ever-expanding class-of-the-week club that 3e D&D fosters.
I understand worries about power inflation in games and its something I openly address in the introduction to Blood and Fists. If you want martial arts to stay in the turf staked out for them in the core rules, dont use the classes in BNF. Its my humble (though biased) opinion that balance isnt changed if you dont use the classes, but at least I try to tell folks up front that using the feats and the classes is adding a John Woo to their game. If you dont want a player to be able to make Chow Yun Fat, dont use the classes.
However, if you're going to make a genre book, which Ive done several of for d20M, I think you need classes.
Why do I say that?
d20M is a great book and hit all the highlights. If you're running a generic game, you have all the archetypes you need. Yes, the "A" word. As much as d20M tries to minimize the issue, classes are still archetypes.
That's why a genre book, or a genre game, needs more variety than the standard class mix.
If you're playing a non-focused game, then its ok for one character to be the soldier, one to be the mage, one to be the wheelman, etc.
If you're playing an all-military game, is everyone going to take levels in the soldier advanced class? In a martial arts game does everyone take levels in the martial artist advanced class?
That's why I try to expand the range of archetype options. Not just to up the power level for its own sake or provide options cause they're cool.
With Blood and Guts you can make soldiers who are very different and the MOS feats let you bend classes even further.
With Blood and Fists you have 3 martial arts classes instead of one, and then again, the Martial Arts Style feats let you bend those classes even further.
Could you do this with JUST the core rules? Well, I guess, but you could say that about anything. Maybe we should all go back to Fighter, Mage, Cleric and Thief.
And no, those classes wont mesh as well with the core rules as classes written by the AUTHORS of those rules. Sorry about that. I have my own take. As long as things arent too out of whack though, I think multiple takes are a GOOD thing.
Obviously opinions vary on this.
Chuck
I'd like to see a few more Adv Classes that are a bit more specialized in areas, as well as having them in one spot ... like having some Adv Classes for dealing with WWII that are more in that flavor ... or even having some that are a bit more spy ala Top Secret 
