Nusenet would need to include some of the elements we see in IRCnext (Slack/Discord style systems) - the ability to tag individuals into a conversation, the ability to mute whole forums for use specified lengths of time. Permalink options to individual posts. First class search capabilities.

I feel like there are a lot of things that are just -standard- these days that would be included automatically just by current convention. Formatted text, mobile interface, embedded media, a11y.

I feel like Discord has a decent basic identity approach: you have an account, but that account can use different nicknames across your different group forums. You can even have multiple accounts to isolate things further. But true anonymity is hard.