[ColdSteel]

The problem is that this isn't a good economic business model for a small company such as MM. They'd kill themselves IMO if they went the whole open source route.

However, many other games, notably all the Quake Games and Unreal Tournament have released source for a sizable portion of their game engines. Quake2 did this in the form of C language DLL source that you could modify and recompile. That way the core game and game technologies that they wanted to protect remained inaccessible and yet it allowed the mod community to do a whole lot more than just play around with some text file settings (flexible though they may be).

That's one way they could go but a game has to be designed for this approach from the start and SE4 probably is not.

It is something they could consider for the future though.