You know what really grinds my gears with today’s rule books? Proofreading and indexes. I think it’s a shame that people go to great efforts to make a rule book look really nice and then they don’t seem to have even given it to a friend to read through before sending it off to the publishers. I’ll give you one example of what I mean “Victory at Sea” (WW1 version) by Mongoose Publishing, every page reference says “see page XX” every, single, one.
As for indexes, I find that the utility of a rule set is directly linked to its index. A good index is a godsend when, mid-game, rule blindness sets in and something you are sure you read just the other day seems to have simply vanished from the text. A competent index is an excellent substitute for a poor memory 😉