Source what exactly?

My first note: Please don't say "They're not going to release the source code"... I already know that. I'm just wondering....

Now for my question; Lets just say Bioware and Obsidian (EA whoever would actually be the ones to release it :p) released the source code today what exactly does that change for kotor modding? What are some of the new things we would be able to do?

Thanks-Supreme Kotor