I think the goal with Strata is to first introduce it in Production, then work towards a way to allow more shader customization. In short, we won’t be getting any accommodation for NPR until much later down the road.
When examining Strata demonstrations, it looked a bit like Blender’s Shader Editor, which made me a bit excited.
Also, refactoring done for Strata may have introduced a severe performance issue with UE 5.1 
:Shader Instructions 2-3 times more in 5.1