Random Wizard is at it again. I didn't answer his first round of 10 questions, but these look like ones I can answer quickly and easily, so here goes.
(1). Should energy drain take away one level of experience points from
the character? Yes or No? If no, what should level drain do?
D&D - Yes, but my current house rule is that the XP go into a "bank" and can later be given to a replacement PC
Chanbara - I didn't include any level draining monsters or spells/magic items, so it's a non-issue.
(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?
Both Systems - sure, I like the rules of "movie world" rather than real world for my games. I usually go with 1d6 damage each round for two rounds.
(3). Should poison give a save or die roll, with a fail rolled
indicating instant death? Yes or No? If no, how should game mechanics
relating to poison work?
D&D - it can, but most poisons have a duration during which there's a chance to save the PC before death occurs (and some poisons don't kill, merely incapacitate).
Chanbara - I've got a whole big mess of a chart for poisons. Part of me loves it, because the effects of any poison are random and could lead to death, vomiting, cramps, shakes, diarrhea, or other fun things. Another part of me thinks the D&D way is easier.
(4). Do characters die when they reach 0 hit points? Yes or No? If no, then at what point is a character dead?
D&D - Yes.
Chanbara - You make a Saving Throw, fail and you die. Make it and you're dying and will die unless you get some attention/magic within a short time.
(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?
D&D - Yes, by the book.
Chanbara - No, spells use a variant of the Chainmail caster roll.
(6). Should all weapons do 1d6 damage or should different weapons have varying dice (1d4, 1d8, etc...) for damage?
Both Systems - variety is the spice of life.
(7). Should a character that has a high ability score in their prime requisite receive an experience point bonus? Yes or No?
D&D - yes
Chanbara - still considering it
(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?
D&D - BX/BECMI ability modifiers (18 +3, 16-17 +2, etc.)
Chanbara - the highest scores give at best a +2 modifier
(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
Both Systems - Five saves based on attack type, or in the case of Chanbara, the Wu Xing (Chinese 5 elements, same as Flying Swordsmen)
(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?
D&D - No spells at level 1
Chanbara - there are no clerics, but all spellcasters get spells from 1st level