Brother MacLaren
Explorer
B/X stat generation, power levels, rules-liteness, resource management considerations, magic item availability, hard limits (18 ability score, 9 HD, -10 AC, etc.) Change 3.5's DC formula to make saves more like B/X, where your odds of making it go up as you level.
Ability scores improved by choosing 1 stat at each level and rolling 3d6 against it; if beat the old score, stat goes up by 1, if fail, get to roll 4d6-drop-lowest next level (if fail again, then 5d6-drop-2-lowest next time, etc.).
Limited spell list from 3.5, using the things that fit the B/X model (very few damaging or offensive buffing spells for cleric, wizard summoning spells rare and dangerous, save allowed for basically everything)
Removal of certain perpetual offenders on the spell list, or addition of a serious drawback (e.g. system shock checks, teleport death)
3.5 d20/DC task resolution mechanic, some races, some classes, multiclassing, and certain PrCs (the interesting ones that involve an actually meaningful tradeoff compared to the base class).
EK, MT, and AT are taken to be the necessary patch for multiclassing casters (with one free Practiced Spellcaster feat). About as good as a multiclassed caster in 1E or 2E. Any other gish-type PrCs should not exceed this power level.
3.5/4E hybrid skill system
Some of 4E flavor ("Points of Light," Feywild, Shadowfell, Far Realm), some of 3.5 flavor (Lords of Madness, Fiendish Codex, Great Wheel, Greyhawk gods)
Greatly limiting buffing by limiting sources, bonus types, and maximum bonuses; absolutely no stat-boosting effects at all except for Gauntlets of Ogre Power (18 Str)
Power Attack like Pathfinder's version
Weapon skills similar to BECMI Weapon Mastery or to Might & Magic VII
Wildshaper, beastmaster, and summoner are druid PrCs with non-casting 1st levels; base druid has no wildshape, animal companion, or spontaneous SNA.
Give the d12 more love
Ability scores improved by choosing 1 stat at each level and rolling 3d6 against it; if beat the old score, stat goes up by 1, if fail, get to roll 4d6-drop-lowest next level (if fail again, then 5d6-drop-2-lowest next time, etc.).
Limited spell list from 3.5, using the things that fit the B/X model (very few damaging or offensive buffing spells for cleric, wizard summoning spells rare and dangerous, save allowed for basically everything)
Removal of certain perpetual offenders on the spell list, or addition of a serious drawback (e.g. system shock checks, teleport death)
3.5 d20/DC task resolution mechanic, some races, some classes, multiclassing, and certain PrCs (the interesting ones that involve an actually meaningful tradeoff compared to the base class).
EK, MT, and AT are taken to be the necessary patch for multiclassing casters (with one free Practiced Spellcaster feat). About as good as a multiclassed caster in 1E or 2E. Any other gish-type PrCs should not exceed this power level.
3.5/4E hybrid skill system
Some of 4E flavor ("Points of Light," Feywild, Shadowfell, Far Realm), some of 3.5 flavor (Lords of Madness, Fiendish Codex, Great Wheel, Greyhawk gods)
Greatly limiting buffing by limiting sources, bonus types, and maximum bonuses; absolutely no stat-boosting effects at all except for Gauntlets of Ogre Power (18 Str)
Power Attack like Pathfinder's version
Weapon skills similar to BECMI Weapon Mastery or to Might & Magic VII
Wildshaper, beastmaster, and summoner are druid PrCs with non-casting 1st levels; base druid has no wildshape, animal companion, or spontaneous SNA.
Give the d12 more love