I keep wishing I could write in collapsible outlines. See the shape of the whole thing on one page, zoom in two or three levels of detail depending on how much I want to drill down, turn on the “designers commentary” layer when I want it or off when I don’t. Actually, now that I’ve framed it that way, it may be doable. I should get on that in my copious free time.

For ruleset a that have a reference form and a learning form — that’s often what game aids are for. Combat flowcharts, the stupidly large “player screen” of all the Shadowrun 3e modifiers, people have even made Fate cheat sheets.

In my experience, players and GMs value making these things themselves as a means of learning and internalizing the material.