I've been working on a project for some time now - or more properly a number of closely related projects - and have been cutting up the d20 system to do it. I'm adding a few things, taking out a few more, and making more than a few adjustments. Up until now I've only posted a few parts of it over at ENWorld's house rules forum, and although I have had some good critiques, after finding this place I realized I could get some solid perspectives from further outside of the d20 box.


First off, some disclaimers:
-This is inspired in no small degree by video games. Part of the aim of this project is to emulate the settings and playstyles of various console and computer games. Not to say that this will use similar mechanics as them, nor be as much or more "video gamey" than d20 is sometimes accused of being, but it is meant be simpler so as to appeal to the more casual gamer. It is not limited to these settings however.
-The basic changes sound like simple d20 house rules, but the mechanics built on them and concepts around aim higher than that. I may not be much experienced in game design, but I do take it seriously and am trying to create something original and of quality.
-This project and it's various forms are all meant to be highly modular, so details and mechanics can be freely added, removed or swapped between each other. This makes getting the mechanics solid, balanced and universal is paramount. I'll be begging for critiques toward this end, so fair warning.
-Some of this stuff might end up sounding like it was inspired by 4e, but I've been at this for much longer than that, honest! All the same, when it does finally come out I imagine there will be plenty to borrow from it.
-I'm still very new here and figuring things out, so if I screw something up or commit some faux pas please go easy on me.



That said, on with the project.

What's Kept
-Classes: Still uses a class system, and they work much the same way. Depending on the setting, this may involve generic fantasy classes, something closer to d20 modern, or a more abstract but similar concept.
-Skills: The skill system remains intact, but individual skills and uses of them vary somewhat.
-Feats: The feat system is used as is, but outside of some core ones games will have their own lists of feats they can use.
-Mechanics: Most other basic mechanics are kept, except those expressly removed or replaced. Ability scores. saving throws, d20 for attacks, AC, AoO's, etc. are all still used.

What's Out
-Vancian magic: Only real remnant of the magic system is the concept of caster level, and that is heavily modified.
-Prestige classes: Although there is some of that concept, it does not involve separate class levels.
-Bonus types: To keep things simple, so everything stacks. To keep things balanced, theres not as much of it. There are also no ability score enhancements, but there are bonuses to what they modify.

What's In
-One spell/ability per level: Video games tend to have less spells for mage types, but other kinds of characters have similar "spell lists". This applies to every class equally, as well as monsters.
-Point based magic/ability system: Can't emulate most video games without it. Points of Mana (or energy, spirit, or whatever the game setting uses) is a function of level, class and ability scores, much the same as hit points.
-Base Caster Level (BCL): Caster level expressed in the form of BAB, and with three similar progressions. It has less role in the effect of spells, but more in their accuracy. Also changes in name/role with setting.
-Capacities: A flipside to the saving throw, this is also based on Fort, Ref and Will scores, but modified with Str/Int/Cha respectively. Capacity is a value whose principal role is to limit the use of gear. There are a number of other uses as well, that very with the specific game.

What's Tweaked
-Multiclassing: Progressions of the same kind and rate between two classes are treated as one. For example, a class like fighter that goes barbarian doesn't start over his fort score progression with another +2, instead he gets whatever another level of fighter would have gotten him. He also gets Ref and Will as the fighter would have, instead of starting over with zero. If the classes have different progressions they are added normally. This applies to BAB, BCL, Fort, Ref and Will.
-Monsters: Somewhat like a combination of classes and racial levels, monsters will have a weak core set of stats, and scale up through special monster classes. These classes typically take the form of monster types such as Dragon, Elemental, Construct, etc, to represent that monsters natural ability and growth over time. Although technically open to a PC that meets the requirements, these classes can't simply be bought with experience since they represent physical changes.



Outside of the magic/ability system, the Capacity mechanic is the only major rules addition for this project. It is also the only one universal to the entire project, since magic and abilities vary greatly from game to game. It is also the basis of many other functions in the games, so I'll detail that first.

Capacity
-Fortitude Capacity (Fort Cap): This is the limit of how much equipment you can wield without falling all over yourself. It isn't a matter of how much actual weight you can carry, but of your ability to effectively attack while wearing armor and using weapons.This score has a value of your base Fortitude and Strength modifier, if positive.
-Reflex Capacity (Ref Cap): This is a measure of speed, balance and organization. It effects your ability to use gear that requires finesse, and to have weapons and items ready to use without having to spend time digging them out. This score has a value of your base Reflex and Intelligence modifier, if positive.
-Willpower Capacity (Will Cap): This represents how much mystical influence you have. It determines how many and what power of magical items or effects you can keep active at once. This score has a value of your base Willpower and Charisma modifier, if positive.

To use any kind of gear, it must be equipped. Depending on the type and power of an item, it has penalties to one or more kinds of Capacity when doing so. The penalty from multiple items stack, and if the penalty for equipping an item would be more than your total from that type then you can not do so. Equipping requires that you have the item on your person, that you be able to use the item, and usually that a move action be taken (armor of course takes longer than this, weapons take only as long to draw them).

More on this to be added later. I have a more detailed version of it for standard the d20 system posted at ENWorld if you're interested, but that isn't the same version I'll be using here.  It does provide a good baseline to compare with though.



That's the gist of it so far. Next I'll get into the the magic/ability system and details of the first major project, Elements, assuming you guys don't run me out of town first.

Let me know what you think!