SpellObjectEnthusiast
Adventurer
AD&D is a rules heavy, crunchy game. So is BECMI - see Weapon Mastery, the class/prestige class system, etc. B/X is Rules Medium, at best. I'd argue its also rules heavy.But the rules were not designed to be optional. That's the whole point here. People just CHOSE to ignore them, or never even realized they were there. But they were.
Even apart from that, though: Again, you want to claim that attack matrices, the five saving throws (Paralyze/Poison/Death, Rod/Staff/Wand, Petrify/Polymorph, Breath Weapon, Spell), and indeed the very concept of "saving throws" in the first place as opposed to just having attacks (they're even named "Attacks" in AD&D1e!), etc. are "rules light"? Or how about THAC0?
Pull the other one. AD&D, and its successors, have NEVER been "rules-light." Ever. Period. Anyone claiming otherwise is either playing sillybuggers with definitions, or genuinely out of touch with what a "rules-light" game is for one reason or another.
Because, as I and others have said, "rules-light" has paragraph-sized as its low end and "12 printed pages" as a pretty typical size. Even the simplest versions of Basic, which I have bent definitions to allow as possibly maybe kinda-sorta vaguely "rules-light," are four times larger than that--and that's for a very barebones offering in D&D terms.
AD&D is not, and never has been, "rules-light."
Into the Odd is Rules Light - the rules are like 2 pages. Lasers and Feelings is rules lite. Honey heist is rules lite. Risus is rules light.
TSR d&d is only rule light if you decide to ignore 95% of it.