The functionality of discovery outside of those you're following varies heavily between clients. Personally I'm pretty happy with Coracle's approach. Between hashtags, and looking at extended networks, I can slice things up to my liking.

That said I'm not opposed to client level algorithms for curating a feed if it's what people want to opt into. At the end of the day Nostr being a protocol will almost certainly ensure that these remain optional, rather than enforced. Personally I won't be opting in, but I get that not everyone is interested in tinkering with their filters to find what they want.