Quote Originally Posted by Rhianu View Post
Personally, I don't think an SDK is necessary in order to facilitate addon development. All that's needed is a library of code functions and a way to run them.
This is true, but SE this time wants "sanctioned" addons unlike FFXI's windower and the like. Remember SE mentioned that addons can be submitted then after a "review" it's either be "sanctioned" or rejected. This gives SE a little more control over usable addons giving them more right to changed server client code to "break" non-sanctioned addons.