I solved the problem with npc navigation in generated levels(the lack of it). Since there's no way to edit ai nodegraph ingame, I had to place thousands of nodes, one for each map tile. And to my own surprise, that actually almost solves the problem. NPCs still bump into every wall before getting to destination, but they CAN walk anywhere now, not to mention simply chasing the player. It's great, because without nodegraph, npc's would have brain aneurysm and stop moving once their target gets behind a corner.
4
You can see all connections of these nodes on the screenshot. There are so many of them, that using the command for showing nodes/links usually crashes the game. By the way, when someone bumps into a wall, the connection is marked red as "bad", so no one will bump into same wall twice, which is also great.