I was torn on breaking down both 1E and 2E into their early/core versus later/heavily supplemented "editions." By and large across editions I think I enjoy the simplicity of just core more, but I kind of think that is from a primarily DM perspective.
That's not true at all. Sure, BECMI has more later, but they aren't exactly the same early on. There are notable and significant differences in thief skills, for example.By that logic, it's hard to consider BX and BECMI separate editions.