I wasn't particularly happy with the way the old URLs were laid out, in my opinion they were very ugly and needed improving:
Here's a few comparisons between the old structure and the new one:
It was a pain to get the new URLs working, as MyBB was not made to use anything but URLs in the root directory. If any links 404 because of the change, be sure to PM me (reporting bugs in the slack lounge leaves the chance that I'll miss them...), so that I can fix them.
We also have a new pagination style: