Gametesting and publishing

[arkcure]

Hello.  I am designing a RPG that is in the intial design phase.  While my friend is writing up the charcter descriptions, i have begun working on a combat system for the game.  

I wanted something different from the usual intiative, attack, defense etc. and came up with something pretty clever.  The system is in it's infancy and I was wondering how important documentation from gametesting is when presenting an RPG to publishers.  I do hope one day to look into publishing, but not for a while.  The question grabbed me so i thought I would ask if any one had any experience that could help.

Thanks
arkcure