I just came across something I put together in April of 2005 as "my vision" of D&D 4e. I was on a simplification kick. Here it is, for comment! It's incomplete of course, but IMO it simplifies the system.
Mxyzplk's 4e D&D
All rolls are 2d10 versus a DC. Margin of success is added to effect (including damage on attacks). On the one hand, this attacks the d20 sacred cow, but if you have lower "point spreads" being able to use margin of success is boss. A couple levels is a bnigger gap with this, but advancement's slowed (see below)
Ability scores – the usual 6, roll (consider 3d6 hardcore, or point buy) as usual. Each stat has an active and passive role:
Str – transmutation, melee attack/defense
Dex – evocation, ranged attack/defense
Con – necromancy, physical conditions
Int – illusion, divination, magic attack/defense
Wis – enchantment, mental attack/defense
Cha – abjuration, conjuration, social attack/defense
(obviously, I did not look at getting rid of the spell schools)
Alignment – clean up, make good more good and clarify law/chaos as more personal approaches than ideologies.
Class basics - All classes gain 2 feats per level - one class bonus feat and one free feat, and gain skill points equal to their class’ skill point allotment. At first level, characters start with one class bonus feat, one free feat, and class + Int bonus skill points.
Level: progression is slowed by about half from 3.5e.
Eliminate rolling for hit points – everyone hates rolling low and it’s the one thing you still have to randomize when you level. Just max out hit dice; because of the wounds/hits differentiation there will be more subdual/fatigue kinds of hit point reducers. All classes have one of the following tradeoffs:
hp sp
12 2
10 4
8 6
6 8
4 10
Each class also has two “good” (+1/level), two “average” (+1/2 levels), and two “poor” (+1/3 levels) stat progressions. These replace the bonus ability score points.
Example Classes:
Class Good Average Poor hits skills
Barbarian str/con wis/dex cha/int 12 2
Bard wis/cha dex/int con/str 6 8
Cleric wis/con str/cha int/dex 8 6
Commander str/cha con/wis int/dex 8 6
Druid wis/dex cha/con str/int 6 8
Monk wis/dex con/str cha/int 8 6
Paladin str/cha con/wis dex/int 10 4
Priest wis/int cha/dex con/str 4 10
Ranger str/dex wis/con cha/int 8 6
Rogue dex/cha int/wis con/str 6 8
Sorcerer dex/cha int/con str/wis 6 8
Thug str/dex con/wis int/cha 10 4
Warrior str/con dex/wis cha/int 10 4
Wizard int/dex wis/con cha/str 4 10
Warlock int/cha dex/con str/wis 6 8
Therefore a L3 Rogue2/Warrior1 looks like:
Frederico Str +1 Dex +2 Con +1 Int +2 Wis +2 Cha +2 hp 22 skill points 20
3 free feats, 2 rogue class feats, 1 warrior class feat
You get more per level in my 4e (stat bumps, feats, etc) but you don't spread too much in level.
Skills
Skills max out at ranks=character level (DCs would be lower to match)
Use skills for combat abilities as well and for schools of magic, and for saves
Rolls are all 2d10 + skill + feat bonuses vs 10 + DB + feat bonuses
In this way attack doesn't outstrip defense
attack skills
Melee attack (STR)
Ranged attack (DEX)
Magical attack (INT) - separate skill per school maybe?
Mental Attack (WIS)
Persuade (CHA) is the "social attack" skill
defense skills
Physical
Block (Str) - defense roll for melee combat
Dodge (Dex) - defense roll for ranged combat
Tough (Con) - defense roll for, you know, Fort savey things
Mental
Think (Int) - defense roll for many arcane spells
Will (Wis) - defense roll for mind-affecting
Cool (Cha) - defense roll for social skills
other skills, generally opposed in the same way
Stealth
Perception
and then random trade skills (including survival etc)...
Feats
In trees. Feats would be your main method of tweaking stuff.
Standardized weapon/spell damages
Weapons
Simple small - 1d4
Martial small - 1d6
Simple medium - 1d6
Martial medium - 1d8
Simple large - 1d8
Martial large - 1d10
et al.
Give piercings a x3 crit multiplier, slashings a +1 damage, and bludgeoning - who knows, something. You can have a large weapon with reach, or without. And that's it.
Spell damage
touch - d10/level
ray, missile (ranged touch)- d8/level
burst, cone (area effect) - d6/level
pick an energy type.
You can get various "special effects" for reducing the dice - let's say 1 die size for sicken, fatigue to 3 for blind, nauseate (so Egbert's Flaming Pooball would do 1d6/level - 3d6 + nauseate 1d4r).
Must roll to hit for everything, and use grenade scatter for area effect spells. This adds a lovely bit of randomness to fireballing close to your party.
You'd have separate amounts of damage spells, perhaps refreshed more frequently than daily, and then a separate group of utility spells. Use spell slots. I prefer everyone to be able to spontaneously cast spells - maybe the 'damage spells' are spontaneous for everyone and the wizards get utility spells while the sorcerers don't.
Hit points - divided into Hit points/wound points=CON like Star Wars
Armor soaks damage
Magic items - +1 is a lot of plus because of the 2d10 roll and lower spread.
Make magic items a lot harder to make - not to 2e levels but way short of 3e levels. Have them be more "treasure" and less "trade items" again.