A way for Wardens to not be cheesed

I noticed Wardens have problems moving through small holes, which is important in the Ancient city. They also can be cheesed by simply building up or placing a bucket of water. My solution is that Wardens should be able to slowly climb blocks, walk through currents with little speed reduction (but still sink), and squeeze through tight spaces through crawling like humans can squeeze through 1x1 tunnels (although, obviously they would probably only be able to fit in a 2x1 horizontal tunnel at best). Another possibility would be for them to dig under and resurface in another area covered in skulk in order to allow them to travel beyond impassible terrain.