As part of my struggle to focus on building a campaign rather than homebrew rule systems that I never complete, here’s another idea. R20 or “if Robert were to run a d20 system game again”...
When I first read Wizards’ third edition D&D Players Handbook, it seemed like a fairly generic game that had been skinned to look like more like D&D. It seemed to me that if they’d gone farther away from D&D (and not called it D&D), I’d probably like it more.
I thought the generic classes from the 3e Unearthed Arcana was a step in the right direction. True20 expanded on that idea, but I’m not crazy about it.
I liked a lot about the “only one class” variant in the d20 Call of Cthulhu, but I’ll put that route aside for now. I didn’t really care for the ability-based classes of d20 Modern. Anyway, back to the generic classes route...
I’m not a big fan of the Expert generic class. Let’s let everyone be an Expert. The Spellcaster and Warrior classes should gang up, kill it, and take its stuff. Spellcasters and Warriors follow the class skill and skill point rules for Experts. It’s kind of fitting that a swords & sorcery game should have two classes: Spellcasters and Warriors.
Next, I’d use “mid20” for probably most rolls other than attack rolls. That means you roll 3d20 and use the middle value. I’ve also considered the 3d6 bell curve rolls from the UA. I also like level-based skills, another UA variant.
Even with all those changes, though, I’m not sure if it becomes a game I want to run. There may still be too many little details in the feats, combat rules, and spells that I’d want to change.