What is the point of being able to moderate *comments* if you can't even moderate *users* and basic access?
I saw a series of posts from 5 years ago that indicated the WP core team thought that moderation of registrants on a WP website should be left to plugins. That strikes me as insane. Probably was 5 years ago, but it certainly is now -- social media, spam, WordPress, and the internet world in general have changed a lot in the past 5 years.
As WordPress evolves and expands into a blog-centric CMS or website framework, providing basic activity-moderation capabilities seems to be a core function. Managing user roles and permissions is a central function that can allow multiple add-ons and plugins to interoperate as long as users/members are managed as part of the core. What's the most fundamental user role or permission? Access and membership itself.
If WP is going to offer any core capability for managing user roles, and for moderating anything, it should start with a capability to moderate user registrations.