Maybe it's a bit short sighted, but to me, it looks like you took the navbar, mirrored it to some degree and decided to put it at the bottom of the layout, why?

What, in your opinion, are the advantages of this design against the former? I don't see any.

Again, i'm not trying to be a pain, but all it manages to achieve in my eyes is to confuse people, rather than creating a cleaner, more intuitive navigation of SN (on mobile, I only use mobile).

There certainly are things to be improved, but the layout and navigation certainly aren't on that list - at least not in this scope.

Edit: Also, the upper part of the layout looks a bit "lost" and empty, while the bottom part looks crowded and misplaced.