I am a big fan of how the belts work and how they can connect buildings on different grids.
I also like the Pathway building blocks as they currently are.
It is just a shame that there is no good way to join Pathways currently.
Having a "auto-Pathway" that uses the same connection method as belts, just between Pathways, would be really great! And would really make building vertical systems a lot easier, especially if you wanted to do different systems in different buildings.