Yeah, it does seem to make so much sense. I guess they are fearful of putting a distribution in the hands of users. Partly because they do like their 'behind the curtain, Algo of Oz' opacity, but also their (legitimate?) fear that users will abuse the system - those pesky growth-hackers - and have people unfollowing or unsubscribing in droves as they get flooded with crap.
One solution to this -and I think I'll write an article about this idea I've just had - could be to have an opt-in, where you can choose to make certain users (the ones you most trust and share an affinity with) personal 'scouts' or 'recommenders'. So if they click to forward a piece, it gets sent immediately/as a daily digest/bumped up their feed only to those who have explicitly sad 'when Person Y recommends a piece, send it my way'.
You could choose to have 0 'recommenders', or 100.
Right now I 'follow' 400+ people. I prune it now and then, but it's a pain - I can't even remember who many of them are, or if I actually am interested in their stuff.
But I could quite easily pick 30-40 off that list whom I would activate as 'recommenders', since I know through interaction with them that we share a lot of interests and tastes.
It's a more organic and naturally human way of doing it than just 'follows' and 'topics'.
Hmmmm....