No matter what books you allow or forbid, your always going to have a munchkin who insists its all perfectly legitimate and proper. Thus, a simple idea; instead of a power cap based on contributions to the end, a power cap based on the end result.
You have this one final stat called "Power", that is derived from the rest of your stats.
Attack: Your strongest attack that can be used against your current enemies is taken into account. Your best possible attack configuration in a round. The attack bonus (or save bonus) is your basic "Attack" rating. Your "Damage" rating is divided by 5; its the maximum damage that the attack can deal. And your "Critical" rating is added on in both ways; 19-20/x2 is +1, 19-20/x4 is +3. Thus, a Fireball 10d6 DC 20 would be rating 22, and a character with 4 club attacks a round at 1d10+20 damage (+15 to-hit) would be 37.
Defense: Your optimal AC is whats used; best possible against the attack your strongest against. Your AC bonus is first, adding on any DR you have, any fast healing is tripled, any miss chances converted to flat bonuses(50% = +10) and added, your highest saving throw, and finally your Hit-points divided by 10.
(Dwarf fighter with a Fort save of +10, A 30 AC, 160 hps, and a DR of 3/-, would have a Defense rating of 49)
Your "Power" is the average between these two stats. Depending on the power level of your campaign, you choose a particular "Power" ranking; perhaps one that scales with level. A player who exceeds his power ranking has his abilities appropriately weakened at DM's discretion; the DM chooses at the begining of each combat which abilities work and which don't. Those whose abilities are below the "Power" ranking get a commensurate bonus that brings them halfway between their actual rank and the assigned score. Fortune favors the underdog?
Regardless; any time the player changes the situation significantly; stacking on a combination of Buff spells to make himself a god; polymorphing himself into a Kraken; his Power is recalculated, and he regrets trying to abuse the system.
A third possible option would be a "Versatility" ranking, based on spells, skills, and noncombat abilities. These would be more level-based; Two per level of most classes, with Fighter possibly being the only one to get a single rank/level; essentially, the less usefull your abilities are outside combat, the more you'd be allowed to invest in combat potential. But that might serve to elimenate the purpose of the endeavor, which is to prevent a single PC from outshining all the rest.
You have this one final stat called "Power", that is derived from the rest of your stats.
Attack: Your strongest attack that can be used against your current enemies is taken into account. Your best possible attack configuration in a round. The attack bonus (or save bonus) is your basic "Attack" rating. Your "Damage" rating is divided by 5; its the maximum damage that the attack can deal. And your "Critical" rating is added on in both ways; 19-20/x2 is +1, 19-20/x4 is +3. Thus, a Fireball 10d6 DC 20 would be rating 22, and a character with 4 club attacks a round at 1d10+20 damage (+15 to-hit) would be 37.
Defense: Your optimal AC is whats used; best possible against the attack your strongest against. Your AC bonus is first, adding on any DR you have, any fast healing is tripled, any miss chances converted to flat bonuses(50% = +10) and added, your highest saving throw, and finally your Hit-points divided by 10.
(Dwarf fighter with a Fort save of +10, A 30 AC, 160 hps, and a DR of 3/-, would have a Defense rating of 49)
Your "Power" is the average between these two stats. Depending on the power level of your campaign, you choose a particular "Power" ranking; perhaps one that scales with level. A player who exceeds his power ranking has his abilities appropriately weakened at DM's discretion; the DM chooses at the begining of each combat which abilities work and which don't. Those whose abilities are below the "Power" ranking get a commensurate bonus that brings them halfway between their actual rank and the assigned score. Fortune favors the underdog?
Regardless; any time the player changes the situation significantly; stacking on a combination of Buff spells to make himself a god; polymorphing himself into a Kraken; his Power is recalculated, and he regrets trying to abuse the system.
A third possible option would be a "Versatility" ranking, based on spells, skills, and noncombat abilities. These would be more level-based; Two per level of most classes, with Fighter possibly being the only one to get a single rank/level; essentially, the less usefull your abilities are outside combat, the more you'd be allowed to invest in combat potential. But that might serve to elimenate the purpose of the endeavor, which is to prevent a single PC from outshining all the rest.