For some reason, comments under a post only nest 5 levels deep and once you hit that limit, you can no longer reply to the last comment. If you want to reply after that, you have to awkwardly find a higher level comment to reply to, which makes the conversations look confusing.
I'm not sure if this is a block chain issue or just a user interface issue. It seems like it wouldn't be too hard to concoct an interface that would allow deeper nested comments. Maybe something like this:
(Pardon my poor photoshopping)
Conversations are important so I think this would help.