D&D 3.5 Concentration Skill House Rules Inquiry: Constitution-Based

[scarmiglionne4]

I am making a different set of skills for my D20 home-brew game and was thinking of doing away with ability score checks and replace them with a set of skills that are class skills for everyone that each start with 3 ranks.

So far I have Athletics for Strength, Acrobatics for Dexterity, Endurance for Constitution, Reason for Intelligence, and Influence for Charisma.

My issues is Wisdom. It seems to me that Concentration should be ideal for Wisdom.

Why is Concentration Constitution-based? Has anyone out there ever house-ruled it to depend on Wisdom or any other ability score?

[Ashtagon]

The primary usage for Concentration checks is to be able to finish a spell in combat; it is for nearly all purposes a caster skill.

Keying it off Wisdom would give Wisdom-based casters a strong advantage over other casters.

[scarmiglionne4]

So it is purely a balance issue.

Because I don't understand what Constitution has to do with avoiding distraction.

[Jeraa]

Constitution is the ability to withstand damage, and the majority of concentration checks would be made because the caster was damaged. (Granted, not all concentration checks involve damage, its just the its far more likely a concentration check would involve being damaged.)

[Temotei]

Of course, you could look at Autohynosis, which is keyed off Wisdom, in justifying Wisdom for Concentration.

[Jeraa]

Concentration could really be based on either Constitution or Wisdom.

According to Charles Ryan (http://www.wizards.com/default.asp?x=d20modern/bp/20030805a), Constitution was chosen to make the distribution of skills more interesting, and to make the game play better.

(I assume by "play better", he meant that basing Concentration of of constitution doesn't favor any spellcaster over another.)