I've always felt that the game needed more NPC's.

Specifically, ones you can find and bring back to your Castle who would then work for you, using the Carts/Roads, and other tools and equipment such as Smelting, Logging, Lamp Lighting. (No Warp-Gating NPC's)

This would finally allow for some mild-automation and actually give cause to building large permanent bases.

I also thought that there should be greater enemy civilizations. The Fulings build small Camps. So why are there no Fuling Kingdoms? Or other Ally/Enemy Kingdoms found?

There are Remnants of crumpled Stone Towers, none which resemble a part of a larger Castle or Community. Yet we know from the Lore presented that there were many that have come before us and settled the lands only to fall.