a casting version of the BAB

[Yakk]

Concepts:
List Level
Tradition Level

Your List level in a class is the average of your class level (including any PrCs that advance spellcasting in the class) and your character level. Your list level is limited by twice your class level (plus any PrC levels) in the class that provides the list.

Each class belongs to a tradition. There are Divine, Arcane and Psionic traditions (and maybe some more).

Your Tradition Level for a tradition is the average of your Caster levels in classes that correspond to that tradition, and your Character level. If a given PrC adds to your Caster level in more than 1 class from a Tradition, it only contributes 1 level to your Tradition level. Your Tradition level is limited by twice the sum of your Caster levels within that tradition.

Hybrid classes (Paladin and Ranger) count has half a Divine Tradition level. Note that this boosts the Paladin and Ranger casting levels to a certain degree.

Both of these values are limited by your character level, and you round down.

Your Tradition level determines your Caster level in a class.

Some "multi-class PrCs" may have to be modified.

...

Examples:
Wizard 10/Fighter 10
Has an Arcane Tradition level of 15.
Has a Wizard List level of 15.

Wizard 10/Sorcerer 10
Has an Arcane Tradition level of 20
Has a Wizard List level of 15.
Has a Sorcerer List level of 15.

Wizard 7/Paladin 3/Eldrich Knight 10
(Effective Wizard Level = 7+9 = 16)
Has an Arcane Tradition of 18
Has a Wizard List level of 18
(Note: EK is a multi-class PrC. Needs to be rebalanced under these changes.)

Wizard 1/Cleric 1/Druid 1/Sorcerer 1:
Has an Arcane Tradition level of 3
Has a Divine Tradition level of 3
Has a Wizard List level of 2
Has a Cleric List level of 2
Has a Druid List level of 2
Has a Sorcerer List level of 2

Sorcerer 3/Bard 2
Has an Arcane Tradition level of 5
Has a Sorcerer List level of 4
Has a Bard List level of 3

Wizard 2/Cleric 2/Mystic Theurge 10
(EWL: 12, ECL: 12, CL: 14)
Has a Divine Tradition level of 13
Has an Arcane Tradition level of 13
Has a Wizard List level of 13
Has a Cleric List level of 13
(Again, a multi-class PrC. This probably need rebalancing. Note that earlier entry is possible than under standard rules.)