There's a lot of supposition about what that should look like. Lots of 'we need to make it like social media' except you can't for all the reasons I outlined before - and while you could make it look like social media, the reality is that you're still fighting against the same fundamental problems: you can't be a one-stop-shop for everything because you're not Facebook and no amount of veneer can fix that.
End of the day, whatever the presentation, you still have chains of comments that form 'topics'. If you follow the social media route and discard boards, categories or even something more malleable like prefixes, all you have left is somewhere between the most recent and the most active topics. Which is fine, I guess, if you don't care about being able to look back at anything, and for some subject matter, that's absolutely fine.
The reality is that the boards, categories, prefixes, whatever, is what gives forums their power. And it sucks to realise that fact, that the single underpinning element is that categorisation matters. Now, how to fix that over time to make it less difficult/less tedious? There's a question we could talk about.
On some forums people have difficulty finding the best place to post. (Heck on Reddit some people have difficulty even finding the right subreddit so we know the board analogue is a pain point, but it's the same pain point.) Which means we start talking about things suggesting places, AI categorisation (something it actually should be good at doing) and smarter thinking around how we lay out forums in the first place.
I think there's also some room for some clever canonicalisation of content. Think about Stack Overflow for a moment, a question is posed, it might collect several answers and the community (influenced by the question asker) will coalesce towards the most popular answer. Now, the most popular answer isn't always the best answer, and it's certainly possible that the answer will change over time. SO is not good about handling this, but the point stands: the conversation arrives at a conclusion that is the canonical outcome. There's room in forums for something like this, particularly in getting from 'discussing something' to curating the best knowledge from that topic.
We see Discourse doing something in this space, around picking out the best items in a topic to give you the highlights as it were, but that also relies on community interaction to help determine that, which isn't necessarily as positive as it might seem. But Discourse prides itself on focusing on the content in a way without the cult of personality that can otherwise happen in some communities, and I'd even give it to CDCK that what they built does that, but IMO at the cost of sucking the personality and life out of the place.
There is also something to be said for being a resource site rather than strictly a forum, which changes the dynamic to something vastly more transactional, in that you offer up resources and you might well have indirect conversation in the form of comments on articles, rather than activity in the forum itself. But I think that also plays into what you're hoping to achieve longer term.
