What makes a game "rights light to you? Low page count? Low crunch? Simple rules? Easy to learn? Easy to teach? Doesn't require players to know the rules to play? Something else?
Discussion and Reviews of rules-lite tabeletop RPGs (games like Microlite20, The Black Hack, etc.)
Playing and Gamemastering Tabletop RPGs Since 1975
Designer: Microlite74, Microlite75, Microlite78, Microlite81, Microlite20 OSS, and others
Compiler: The Microlite20 RPG Collection
Administrator: Microlite20 Nexus
Rules designed in a way that I don't have to refer to them in any way, and that I can easily incorporate into my narration of the gameplay for the players. So, they don't have to refer to anything either.
I come from a Fate Accelerated background, if you don't know much about it, it is a very light system that can be adapted to any scenario (from futuristic cats flying spaceships to classic elves and wizards dungeon) and is focused on roleplay and the situation rather than algebraic calculations to figure out stats, AC, DC, level bonus and stuff. The game uses what is in the scene, and facts about characters to create 'aspects' such as "The bridge is collapsing", "top marksman of the rust guild" and "Was betrayed once, never again" to give the characters and world gameplay substance. there are no spell tables, race bonus charts, AC calculators. There is one type of dice which is used, and basic stats, the meat of your character is their aspects and high concepts. Most of it is up to the players and DM to focus on the story they are making together, that is the aim. This is defiantly rules light.
I have also participated in a few sessions of what the DM called "Mechs and Syndicates" (It was tabletop RP inside of an online game, so the tabletop setting was based on the online game we was already playing... yes). This was played all through text in under an hour (with frequent distractions that the online game in question presented) and was an amazing experience. There was no dice rolling, you simply say what you wanna do and the DM works with it into the story and narrates what happens. Character creation was as simple as presenting an ingame action figure and saying what you did, such as being a mech with rockets, a wizard with fireballs or a crazy janitor who can clean any mess. This, despite no real rules or any dice, was great and the most 'rules light' you can get.
Rules light to me is basically having the focus being on the game, as soon as you are multiplying level by AC and DC with modifiers calculated by x dice - y dice... it gets into a big mess, keep focused on the story at hand, the characters in it, and any dice being simple.
I would think that the objective to a table top is collaborative story telling. The DM provides the setting and balanced interaction, characters interact with the setting. With this in mind, if the intent of players and DM are collaborative, then mechanics beyond a simple and scaled approach are unnecessary. Rules light would be confining the mechanics to only those essential to provide an objectively balanced game without hindering creative growth.