EASA is preparing a change to the rules for design and production to make them become risk based.
The plan is to create a system that allows to adjust the rigor of procedures and oversight to the elements where risks show the need. This should lead to a system that is proportionate and provides a continuum that fits between the national systems and the full Monty of the current Part-21. It is not just to cover the gap up-to 600kg MTOM and should support innovation! Instead of focussing on rules only, it should become a system where rules, safety promotion and oversight work as a set of tools.
Therefore, the US de-regulated Light Sport Aircraft (LSA) system is a reference, but certainly not suitable for the entire range or innovative designs.
Later in 2018 EASA is planning to share the direction of thoughts via an Advanced Notice of Proposed Amendment (A-NPA).