Have you spent much time on the internet, or these forums specifically? If so, you had to know tangents would take over.The thing is, while this is a valid question (and despite what I say in the beginning, I think there is absolutely some modularity to 5E), it really wasn't what I had in mind. I was much more interested in discussing what a 5E that could reasonably emulate all editions within it would look like (which is what Monte Cook and the early design goals of the playtest indicated). The fact that most of the pages discuss not this but prefer dunking on the thread by saying "5E IS modular, duh" or going off onto a tangent about quality is a bit sad (also, once again, the point about OSE's model of genre rules is completely ignored!).
Particularly with this rather difficult topic. I mean, you're asking us to consider how to design a game that would provide the modularity to not only emulate all editions of D&D, but do so at the same table. That is a lot of possibly completely fruitless work. Not something I generally want to tackle as I browse around these forums.