DEX helps saving throws
Never noticed this before, but it's right there on page 11 of the PHB. I always wondered why Thieves had crappy saves, but now it makes sense. Against magical attacks like fireballs, they will typically have very good saves due to generally better-than-average DEX scores. Against mind altering effects, their saves will generally be mediocre due to lower WIS ("generally"). Essentially, the saving throw tables take into account archetypical attributes and assume their modification due to ability scores. Once again USING ALL THE RULES makes sense. But, once again, the fucking rules are spread out across multiple books, sometimes in places easily glossed over and forgotten. Taken with a retrospective look, 2nd edition AD&D should have been collating all the rules into an easier-to-understand form, not completely suck all the flavor out and rewrite crap. Corollary, Unearthed Arcana didn't help.
AD&D originally had five alignments
Yep. It's right there in the Monster Manual. This is a natural outgrowth of the Law-Neutrality-Chaos scale I talked about before, and explored (apparently) in the Holmes Revision of D&D. Between the publication of the MM and the PHB, it looks like someone decided it naturally followed that alignments such as Chaotic Neutral and Neutral Good were valid choices and thus included. Again, this makes sense due to alignments such as Chaotic good (neutral tendencies) in the case of brass dragons. Brass dragons are Neutral Good, but due to the five alignment system, shoehorned into Chaotic Good. Or something. Sylphs are Neutral (which looks to be a running theme with woodland creatures), but with a parenthetical "good". Going back to the post I made about alignment, Neutral is in fact "neutral to monsters-vs-humans". The good descriptor for sylphs just means they're aren't inimical to anyone, but don't concern themselves with the Law-Chaos war. Or something. There are obviously many different interpretations to be made here, but to be perfectly honest, the five alignment way works better than the dual axis system introduced in the PHB. It also makes me wonder if the MM was in fact meant to be a solitary release. Probably not. But it does demonstrate (again) that there were rules changes during the publishing of AD&D. It also means AD&D was supposed to be a revision to D&D, not a new game. Sorry, Arneson...this brings up another question: what was the real point of B/X and the Mentzer sets? To fuck Arneson over as many have pondered? Just using what I've seen in the printed text, that's the only conclusion one can reach. AD&D is really D&D 2nd edition, B/X is D&D-light. Or something.