I've not implemented namespaces in AngelScript yet. A static method is just a global function in the namespace of the class, so can only be supported once I have namespaces.
Improvements will always come. You may be interested in the new 'shared code' feature that I'm implementing for 2.22.0. It will allow multiple modules to share the same classes (not just interfaces as before). I will eventually expand this to allow sharing of global variables and functions too, though not for 2.22.0.
What exactly did you have in mind with improved module importing?