Just a weird idea that poped to my mind.
In order to make games simple and accessible while remaining deep. I was thinking in forcing myself to have a simple 1 page rulebook. And if the book get's too big it's a proof that it's too complex.
By 1 page, it's not necessarily the final print of the rules that are 1 page, but rather the prototype version of the rules that are 1 page, RV from the setup to the game end. (excludes components, scenarios, etc)
Not sure if it could be an interesting restriction to deal with. Is it too much artificial? Of course, you can change font size to cheat, but it's really just a rule of thumb for yourself. As the real rule book with illustrations will have a few more pages.
It reminds me of older games that came with a single page of rules.
There is a game that comes to my mind: "Lumis". It's very simple and very elegant. It focus on a single experience and does it well. It has just enough.
But it's now always easy to know if your game has too much or not enough. I thought that the 1 page could serve as a rule of thumb.