We made it through with a rather large group of mid-high to high lvl characters and Im still not sure for what lvl range the place is designed (which can be a good thing)
The large number of small spiders makes things quite difficult at times, it's almost impossible to click on them to attack when a (single) group member is already in melee with them.
At the same time they add to the atmosphere, therefore they are good to have there.
Perhaps a solution would be to add a few larger ones as well. As mentioned I don't know the intended lvl range for the dungeon but I was thinking void spiders would add to the horror quite a bit (after all, we are here to make our characters suffer

)
Void Spiders would also fit perfectly into the place in my opinion. I was half expecting to have some jump me while going through those shadowy places.
The xp seemed to say that everyone up to lvl 20 was welcome there. Depending on the intended lvl, this should probably be adapted as well, either by making it more difficult or by capping xp for lvl >15
The crafting drops will mean that this place will soon be farmed to oblivion. If the place should provide those drops, perhaps it would be better to have a special kind of spider (possible a large one) that drops it instead of the small ones, as it did not help to have literally hundreds of bags on the ground when navigating.
The traps there do not require a (professional) tapper, which means this place will soon be soloed by single wizards, while nobody will want to take a trapper to this place, as its already cramped. The traps also did not seem to pose enough danger to make everyone wait for their removal. I think for the port area, most characters will be able to just take them on with high saves and wards.
The enemy casters did not get too much action as they were usually appearing right in front of the group. Perhaps those could be spawned further away, possibly with additional spiders in between them and the group/spawn trigger point. Maybe have a void spider protect a caster, so that one would have to choose between who to fight first.