Fill it to the brim with clearly marked optional and alternative rules. Maybe sometimes with no default rule.
The Kids These Days™ (who, by the way, definitely need to Get Off My Lawn™) are entirely too concerned with the "official" D&D 5e rules. House rules are a lost art among the neophytes, and "homebrew" (which used to mean writing your own entire game) still carries the same soupçon of disdain that it always did, but now it just means creating your own game content—you know, that thing you're supposed to do normally.
Bah. (I'm a Millennial and not a Boomer, in case that isn't clear, but still, bah.)