There's a lot of debate about this as a general topic, not just here.
On the one hand, presenting a list of what's new content is surprisingly popular. Many of the newer community platforms do this by default to showcase the most recent content across the platform, in the sincere belief that this is more interesting for people who discover the community when they're not discovering it by deep-linked content.
This also works if you don't have deeply nested categories, and instead have a selection of top-level categories only that you can sum up with a single word/short phrase (as you see on Discourse and Flarum navigation)
On the other hand, the highly categorised nature is good if you want to find something - but it can be off-putting for people to come in and find somewhere to go, because actually, while it seems like it might be highly structured, people aren't good at finding things by structure unless the structure is obvious, and for most large forums, this isn't necessarily so. Or at least, not obvious at a glance from an external source who might just look at it and go 'actually, nope'.
And that's before we get into the debate of 'doing something different for logged in members', where having the 'latest unread content' is infinitely more valuable than either the generic list of 'what is new' or the category listing by default.
