Import Systems

An import system enables connecting the inside and the outside of a language from within a language. Imports or includes are declared as statements which get resolved by a preprocessor, compiler or a language runtime. Particular solutions such as those of C/C++, Java or Python are well known but hardly ever reflected except when people struggle once and again with one or another.

What are the states of the art in 2013? Are there innovations? What are the perspectives considered under different aspects such as security, ease of configuration and robustness? Should a loose organization wired by external configuration files or a "classpath" be preferred over forms of a more strict organization like a plugin repository at a dedicated path? Is there an abstract, platonic ideal which conflicts with the gritty reality of real operating systems?

Just to avoid misunderstandings: I'm not asking for advanced module systems and import expressions which might contain parameters, inject dependencies or call for dependency resolution solvers which choose between module variants - at least not as long as it doesn't contribute to the idea on how a language relates to its environment.