I see the demand for that, but I’m not totally sure if they really undestand that. After a month they try login and will fail. And then an admin must deal with upset (pre-)user whos login credentials are broken.
I don’t know… this is an issue of trust, but generally it is totally normal that e-mail must be used. Sure, this could be choise of admins too. Just like I have de facto option not to use trust levels (I give right away higher trustlevel and freezing that).
But I would trust on Discourses way to clean unused accounts and keep those users on TL0. To get higher rights email must be given.
I reckon this is not the easiest task because it kind of breaks fundamental functionalities of Discourse. But I don’t know.
I would use such light version. If UX wouldn’t be too complex. But my needs has nothing to do with users’ unwillingness to give email, but to make whole process much easier and catching lurkers (do we have more correct name for those?)