There are several issue with pathfinding and I think that design of the levels is what has wrought the entire thing to pass tbh. It might be too late to fix but in general I think its a dumbification of all gamers out there in order to make people not die to often that has caused this.
After extensive use of spiderclimb, fly, dimension door, jump (both spell and regular) as well as misty step I have come to this conclusion. Why?
First of all there are several places where jump, misty step and dimension door can be used while fly cannot and spiderclimb. Why? Its not merely a pathfinding issue as there is clear line of sight to the destination and no obstructions in the way. Take for instance the library. One should be able to fly through it from one end to the other but as it happens there are squares that are not ground that are essentially no-go for anything. Had they been flight-approved or teleportation-approved that would have been possible and I think the design-issue comes from this. The devs has simply removed squares where one might fall to death from movement in a vertical direction.
Just think of a cube made of cubes. 6x6x6
At baselevel only the corners are accessible on foot. All walls on the cube are solid. The rest is a deaddrop into the beyond... Its possible to use dimension door to move around, its possible to misty-step, its out of reach for jumping and we cant walk over there. But flying really should be possible but since the cubes now by default in the given case is out of reach then that means we cant get there even though its open space cause there is not even cubes vertically in order to circumvent that big drop or any way to simulate it. Also change in elevation is not taken into account when considering movement for fly which breaks pathfinding
A solution for this is that for each cube in a given map all access should be based on a status really. Each character has statuses for each type of terrain they can move through. Be it "Air" "Wall", "Ground". If status is lost for the char and that results in death by falling or so then so be it is my two cents. Otherwise the system is far too limited.
By using tags such as for example "Ground", "Air", "Wall", "Solid" one could make better use of every cube in order to allow/disallow movement rather than removing some cubes from movement all together. This by matching movement-types for chars vs terrain with some restraints in terms of verticality (when climbing is needed for instance).
Most would also just include sets of movements that are impossible. (such as gaps for jumping in case distance is too far)
Im going here cause there are spells that makes a character intangible/incorporeal which in turn means that movement through walls should be considered. Also opens up for illusion-spells such as walls that are not solid. It could be detected by someone that accidently walks into it... or sees through illusions.
Im going here cause pathfinding is a bitch...
Im going here cause friendly chars walk into sphere of fires while they really should avoid it.
Bow before me! Or d'ont. I'm not very picky about these sort of things.
“You can't just turn on creativity like a faucet. You have to be in the right mood. What mood is that? Last-minute panic.” ― Bill Watterson