I think the cost of palisade wall straight sections should be increased, and the cost of cornerposts (after the first) decreased. Right now straight sections cost 3 blocks per tile, while cornerposts cost 30 and gates 15. This has some weird effects on how players build walls, with many more gates than necessary and as few corners as possible. More importantly, it also means enormous enclosed areas are commonplace, and building outside walls is extremely rare for anyone that builds walls at all. The map is more fun to navigate if big box palisades aren't everywhere, so decreasing the cost of cornerposts and increasing the cost of straight sections would seem to do a lot of good things all at once.
I think adding a rope cost for gates (one for width 2, two for width 3) and a cloth cost for visitor's gates would also be good. The idea behind visitor's gates is for them to be used by visitors, but over 90% of those I see are only used to apply the debuff to anyone stepping through so that fence gates behind them can't be interacted with. That's clever and all, but it's ugly when there's dozens of them around an enclosure containing a million map tiles.