Sins has changed a lot since beta 4, no doubt about that.

Here are a few answers to the modding questions: mysql.dll is deleted in final, it was vestigial from ICO. Abilities are very expandable. That system is a large chunk of the core of the game and it is practically a programming language in itself. Some of the AI is modifiable and some isn't though its on the list. As a general rule, we'll be expanding modding over time based on demand, we'd hate to do a lot of work and implement things that won't get used. You will have absolute full access to the entire data file structure for every IC file type. We'll provide a full human readable text version of every IC data file and a tool to convert them to binary. For example in the beta versions the mesh and particle files were in binary form but Sins also loads the text forms (as you can see from all the .entity files which are in binary for final). This should make creating custom tools much easier. Jamie just added a mod management system so you can select in game which mod you would like to play. It will check for assets in the appropriate mod folder and fallback on Sins primary assets if they aren't found (so you don't have to transfer around multiple gigs of files if you only changed a few things). More to come in another post or announcement.