These don't seem to make use of http://openbadges.org/ unfortunately.
We probably will use openbadges - https://github.com/berekuk/questhub/issues/40. But they are not implemented yet.
>product-wise
Are you implying you released a half-baked product? Nothing wrong with that, but you shouldn't wrap it up like that!
With that being said, of course there are lots of plans for improvements (most of them listed in Meta realm), but people, mostly from Perl community, used it successfully for a few months.
I expected to be able to attempt other peoples' quests, but I don't seem to be able to. Is that outside your scope, just not implemented yet, or am I simply missing it?
If quest is based on a stencil, you can take the same stencil for yourself.
Otherwise, it's a feature called "Cloning", and it's not implemented yet: http://questhub.io/realm/meta/quest/51f7ab8688a70b5f74000046
It's a neat idea, I'll have to check out the meta-quests.