Currently if you have a category set for all users, but the setting "Show reg-wall for long posts (prompt users to login to view the rest)" enabled, it still shows the comments under that post. I personally don't want comments visible either until the user registers.
So I would love to see this also hidden behind the Registration Wall and perhaps something that shows how many comments there are.
I know not everyone would necessarily want this feature, so perhaps you could add a setting inline with the Reg-Wall one to enable/disable this.