Implementing anything like this is intricately tied with the work of opening up the core to be expressed more so in wikitext and thus hackable. In particular we need to provide affordances to replace the current JavaScript only hooks with equivalent wikitext based affordances. This is a non-trivial amount of work. Parameterized transclusions are the first step in this direction.
Trying to address the expressed needs independently of implementing wikitext affordances for hooks would likely lead to two similar but conflicting mechanisms for customizing core behaviour.