Important features? The script really is EB, you'd have no reforms, no 4turns per year, no gouvernment buildings placed for AI factions (and thus no recruitment from AI factions) and most factions would go bankrupt after the first turn. And there is more... You really should'nt play without the script, it's absolutely gamebreaking.

Also there is no way to run the scripty automatically, so you have to activate it every time you start a new campaign or load a savegame.