This doesn't mean that crunchy automatically means better, but the rules-facilitated process of TTRPGs is inherent to the form, it's a requirement, and the crunch is necessary for a reason. Robust rules build shared physics and give contour to the game's reality, they create opportunities for the unexpected and unlikely which requires enough inputs for people to *have expectations*, it provides opportunities for complex meta-storytelling where the rules themselves inform how the world is interacted with, what is trustworthy, etc.
Rules lite systems inevitably eat away at these crucial aspects of tabletop gaming. Just play Munchkin, there's literally nothing wrong with that!
@PallasRiot
I think the conventional separation here is kinda dubious because it's slapping a linear continuum on what's more of a multi-dimensional space.
This comes from experience with PBTA, particularly seeing a mix of good games and bad games — the former have many of the virtues of the "rules heavy" game you mention with a structure most people call light, while the latter end up committing the cardinal sins of "rules light" (half-baked, generic, doesn't do much) that you mention here.
@PallasRiot
A lot of this has to do with what the rules *do,* imo.
Part of the hostility towards the big-book games is that a lot of them carried around rules that didn't really work, didn't really add anything, or bogged the game down in reference-hunting or plodding procedural resolution.
But you're very much right that a common failure mode of "rules light" design is "step 2. draw the rest of the owl" — a homeopathic game, a barely-there sketch of a game you gotta finish building in play.