you would have object oriented functionalities, inheritance and so on. And to script new objects in a more structured way would be way easier and more traditional than have the include approach of actual script system.
inherited functions, constructors and deconstructors and so on.... it would just be more natural and more similar to almost all the rest projects that require scripting.

And also you don't have to carry on a script language to mantain, correct bugs, etc,  since all the functionalities are already built in and mantain by python (or the other languages) developers...

I think that clonk script system is a child of an era where languages were way more complicated and so I understand the need to develop a "ad hoc" script system that could be easier to use especially for non-developers.

But with modern script languages I think this is not a requirement anymore...

Btw I speak as a guy that knows clonk scripting language and still doesn't know python or ruby (plan to learn them in the next weeks), but I think that I wouldn't mind the transition if than would achieve a better overall project.
At the end I am approaching python now and I have the feeling that in a couple of days I already know it quite well (ok I knew many other programming languages, but if you know c-syntax like clonk scripts it's really easy to switch anyway...)

For modders all they have to learn (and it would be a good thing to do anyway i think) is a bit of object oriented programming (if they want to use it), for the rest the transtition would be almost harmless...