But I don't do it with every class: I've talked about doing the druid without spells before, but then wrote up a druid class that doesn't work entirely like that. My reason: I use the traditional "with spells" paradigm for classes with a wide range of knowledge-based powers, but use the "without spells" paradigm for those with a more limited range of powers based on commanding or bargaining with other beings.
The "without spells" approach is based on the reaction roll, and the interpretation of Turn Undead as a reaction roll: subtract the HD of the creature being commanded from the level of the character making the command, double the result, and use it to modify a 2d6 roll. On 9+, the command works. Thus:
- 1st level Cleric turning ghoul: 2 x (1st level - 2 HD) = -2 to roll (effectively requires 11+)
- 1st level Necromancer controlling skeleton: 2 x (1st level - 0 HD) = +2 to roll (requires 7+)
- 1st level Beast Master controlling 2 HD wolf: 2 x ( 1st level - 2 HD) = -2 to roll
- 1st level Bard charming 1 HD guard: 2 x (1st level - 1 HD) = +0 to roll
I wouldn't replace the M-U class with a single "M-U without spells" class with broad powers, but I could see using the Necromancer and the Mesmerist as a template for other narrow-power, themed classes, like perhaps a Conjurer or Alchemist. I may write those up at some point; I did do an alchemist once, but not using the "without spells" paradigm. But I can tell you right now that any new class that can create scrolls or another consumable magic item (like potions for alchemists) would use M-U experience/HD tables, while those that are more like limited fighters or thieves with some extra powers (like the Beast Master or Bard) would use Cleric experience/HD tables.
That's enough information to "roll your own class", so to speak.