Because I like it (and don't like things like the 30-day challenge), I'm answering Top Ten Troll Questions Part Two.
(1). Should level drain take away one level of experience points from the character? Yes or No? If no, what should level drain do?
Yes. It should be reversible with some spell though.
(2). Should the oil used in lanterns do significant damage (more than 1 hp in damage) if thrown on an opponent and set on fire? Yes or No? If yes, how much damage should it do?
I prefer Holmes's rule of 1d8 on the first turn, and 2d8 on the second. It does a lot for a group's tactics to have the fire option.
(3). Should poison give a save or die roll, with a fail rolled indicated instant death? Yes or No? If no, how should game mechanics relating to poison work?
Poison is save or die unless specified otherwise. Specifying otherwise is good.
(4). Do characters die when they reach 0 hit points? Yes or No? If no, then at what point is a character dead?
I prefer that characters die when killed. I do sometimes use a d6 to determine how many rounds dying takes; if a character is taken below 0 hit points, the "negative" HP are factored into the die roll (i.e. at -2 HP you take d6-2 rounds to die). Magical healing is possible while dying, but no "I bind their wounds" - it's a mortal wound.
(5). Does the primary spell mechanic for a magic user consist of a "memorize and forget system" (aka Vancian)? Yes or No? If no, what alternative do you use?
Yes. Though I like the Holmes scroll rules, as I've discussed here multiple times.
(6). Should all weapons do 1d6 damage or should different weapons have varying dice (1d4, 1d8, etc...) for damage?
I go back and forth on this, because I mainly prefer OD&D and Holmes, but I also like different dice. If I'm running straight-up OD&D or Holmes, I use d6; when running Moldvay or S&W, I use variable damage dice.
(7). Should a character that has a high ability score in their prime requisite receive an experience point bonus? Yes or No?
(8). Should a character with an strength of 18 constitution get a +3 bonus to hit points, or a +2 bonus to hit points, or a +1 bonus to hit points or no bonus to hit points? And should other ability scores grant similar bonuses to other game mechanics?
Holmes and Moldvay agree: 18 Constitution gives +3 per hit die. My ideal is that Strength gives +1 to hit for 13 or higher (-1 at 8 or lower), and Wisdom gives similar bonus/penalty on save vs. spells. Intelligence gives you languages, and if you read this blog you should know I think that's a terrific ability.
(9). Should a character have 1 unified saving throw number, or 3 saving throw types based on ability scores (reflex, fortitude, will), or 5 types based on potential game effects (magic wand, poison attacks)? or something else?
The third most popular post in this blog's history doesn't lie: Save vs. Death Ray!
So on that basis alone, 5 saves, as long as one is Death Ray.
(10). Should a cleric get (A) 1 spell at 1st level (B) no spells at 1st level (C) more than 1 spell at 1st level?
B, no spells at 1st level. Clerics in older D&D should be gaining levels quickly. It also reduces the feeling that they are "heal-bots" that you get in AD&D, and makes their healing magic more of a valuable resource.