Thx for the short review.
That's the bad wc3 pathing. Smaller paths with a width of 1-2 pathing-pixels (like for the stairs) are often not recognized correctly it seems, especially if further away.
Only if you first send a unit to the beginning of such a narrow path (like the bottom of a stair) the unit will recognize the narrow path correctly and walk on the wall correctly with the next order. Maybe I can enhance that with scripting, but that won't be easy...
Yea the weather effect is kinda supposed to be very intensive. The idea is that you can really see less when the weather is on heavy fog etc. I think that creates a nice atmosphere. But I'll try to enhance the weather system (like smoother transitions when changing) and mabye toning down everything a bit.
That's definitely a bug (wall units weren't replaced correctly). Were it just some walls or all walls (and also the towers?) and do you know what happend at that point of time? Was a wall partly or completely destroyed or was a wall constructed or rebuilt? Every hint makes it easier for me to find the bug.
But in any case I'll look if I can recreate and solve the bug.