Currently, hunting dogs and attacking NPCs will move the shortest distance by tile count towards their target. This leads to undesirable behaviors in pine mires: dogs that can easily chase down a fleeing animal will be slowed wading through several tiles of water, while attacking NPCs can be trivially kited through the water, fatiguing them and leaving them vulnerable to ranged attacks while they're in the water. A damaging hit against a fatigued NPC in water can quickly become lethal, since they fall unconscious and drown.
I don't think water should be an impenetrable barrier, but increasing the weight of water in the pathfinding algorithm by 4x or so would help a lot. NPCs and animals should also be a little more cautious about crossing ice, but that's a secondary concern.