To be honest i have no idea if it would even be possible to implement this but here we go:
I would like this kind of Navigation bar be added to the bottom of the page as well, it would help the browsing if you didn't have to browse back up to navigate to earlier subforum
Personally I use the "maximum amount of posts" -display so the pages are really long, and become even longer with pictures etc - this is why its hassle to scroll back up to go back to the subforum
threads already have page(number) navigation on both at the top and at the bottom of the page so why not this too.
PS: In case I'm mistaken and this is just a function you can turn on/off somewhere could someone please point out where that would be.