Burning Wheel is NOT rules light. Neither is Torchbearer, really. FitD is also kind of mid-rulesy, and yes some PbtA and Fate are very light, but some are more built up than others, and even many of the light ones are more crunchy than D&D / Pathfinder in some areas. Honestly, I find the whole rules light vs not rules-light distinction not particularly useful. It is much more useful to ask of a game how are its rules light and how are they less so. Where does it choose to place the bulkier bits of its mechanics and what kind of experience does that help produce. Additionally there are other metrics that matter, like is the game best for running shorter runs of 6-12 sessions or does it perform well at longer runs, how PC vs GM driven does it tend to be, at what GM prep-level does it best perform, how much and what kind of character growth are baked into the system, what styles of play does the game best simulate and how rigidly does it adhere to these (tactical combat, investigation, heist, survival, intrigue, etc.), and so forth. For example, Burning Wheel has a highly nuanced system for defining character beliefs, goals, quirks, traits, and tendencies and it makes these elements the very mechanical center of play. This produces games that are extremely PC / player driven and highlight a pretty deep sense of agency and character growth. Torchbearer is a life-is-hard grim-dark fantasy survival game. It has rules for managing your inventory that make D&D look like Uno and really give a sense of managing scarce resources that D&D rarely gives. It produces a MUCH better higher stakes dungeon crawl procedural experience IMHO than any version of D&D I have ever played. Blades in the Dark has a whole range of meta mechanics around producing mission/job-style play for a group of scoundrels. It also tracks different metrics of this group's gang, its territory, and its relationship to other gangs. D&D has none of this heft. Or even a game like The Veil that I suggested, it is PbtA, so much lighter than D&D, but it has mechanics around tracking the ever evolving emotional state of the PCs and it uses this to drive rolls in place of where something like Attributes or Skills might usually be used. In that game everyone is constantly thinking about how their characters are feeling and this becomes manifest in almost all uses of the mechanics. So on the whole, yes, The Veil has fewer rules and bits than D&D, but that is a much deeper mechanical treatment of part of the narrative than D&D affords in the same area. D&D then is not just generically "rules-heavy", it is rules heavy in very specific ways. D&D really likes long-ish metered spatially tactical turn-based combat with that being overwhelmingly its most complex and pronounced meta-mechanical framework, it likes lots of character build options that are very concretely defined within the mechanical-narrative space, it likes heroic power growth/creep, etc. Respect to the game, I played a ton of it for 15+ years, but I just got bored of that style. I like crunch, but I am over THAT kind of crunch.
