@Aplateofmomos yes, 100% agree. but IMO there is potentially one saving grace: see their physics site which has "questions", "meta", and another section, "problems". Or photography with a FAQ section. I.e. it is already technically possible to implement your points 2 and 3 there

I haven't heard about that site before. Would that be a suitable addition to the post "Useful mathematical fora" on the main site?

I mean the Mathematics section (community).

And maybe, if somebody has positive experiences with that site, it could be added to this post on MathOverflow Meta: My question was closed on MO because it is not research level. Where should I ask instead?

@MartinSleziak you're the last person I expected to introduce a new site to :) I didn't suggest it because I was hoping for it to improve out of 'infancy' first. But maybe that's a self-fullfilling prophecy. One of the mods there is a MO user (Peter Taylor)