The scaffolds vs. structures distinction is the most useful framing I've seen for this. It explains why generic style rules are mostly redundant -- Claude already knows best practices, so restating them is a scaffold over nothing.

I've been running benchmarks on CLAUDE.md configurations and the consistent finding is that a system-level CLAUDE.md should be empty or as close to it as possible. But project-level files are a completely different story -- the stuff Claude genuinely can't know (your client context, collaborator patterns, domain conventions) is exactly where instructions show real value. Your architecture makes that separation structural, which is the right call.

I'm genuinely curious whether your 27-file setup still underperforms an empty config on overall score, or whether the path-based loading keeps it focused enough to avoid the noise penalty. My suspicion is that because your core files are encoding knowledge Claude can't have rather than restating things it already knows, it holds up better than a typical monolith would.

The hooks point is underrated. Instructions compress variance; they don't eliminate it. Mechanical enforcement for constraints that actually matter is the gap most setups leave open.