Getting both sides of this arg: basically 'sep of concerns' is viewed as being 'seperation of technology' rather than actual sep of concerns. Eg, put documents and styles and behaviour for a related component together, seperate that component from other components.

It's a slightly silly argument because really we're arging between slicing something vertically (tech) vs horizontally (components) and the nicer thing is probably to do both - have lots of components with the documents, styles, and behaviour separated out within each component.