Orius said:
Perhaps those rules are in the book preciesly for the benefit of more novice players and DMs. When I first started out, I too was a much more by the book sort of guy. These days, however, I'm more comfortable tinkering around with the rules and such because I understand game balance better.
I'm sure that is a large part of it. To some extent, the Moldvay "Basic" set had these guidelines, because it only dealt with levels 1-3 and a limited selection of monsters and treasure.
You find Gary talking in early Dragon articles about the need for Balance in AD&D, particularly in the monster/treasure and advancement areas. It's quite strongly stressed in fact... but I've always found that he failed to give solid guidelines, which is a pity.
Thus, 3E, with its much stronger guidelines on advancement, challenges and rewards is more strongly in the spirit of what Gary was trying to achieve with AD&D.
Of course, as Grodog notes, the extra rules can be too confining! I do believe there is a big difference between
running a game for 3E (where I can be extremely free-form and lax in my rules adherence, whilst adhering to the spirit of the rules) and
designing (professionally) for 3E, which requires a much greater adherence to the rules.
Incidentally, the biggest area of rules errors normally comes with NPCs and monster stats - once you get to spells and magic items, the rules are not as strict.
Cheers!