WU will never be good for PVP because of the rampant cheating and mod exploiting there is. In every PVP server I've been on lately, people (maybe understandably) try their best to get an edge on others and so far that includes:
-Mod that lets you see untapped veins on the livemap mod
-Mod that lets you see through objects and landscape and highlights where other people and animals are
-Mod that hides trees with a command so you just see a big barren landscape and can chase people without them having a chance to hide
-Mod that lets you lock the time of day at a certain point of the day, meaning you can make it eternally day
There is no cheating protection on WU and GMs have no way of making these players stop, and no tools to find out wether they have them on or not. All these mods are client side, with the server having no way to make them stop. Literally all I could see GMs do is say "please don't use this".
It just kills any will to play when you either have to go into the cheating meta or just play normally while in the back of your head you never know if the guy in front of you has all that stuff activated. When WU just came out you could just lose people by going into a forest and doing your best to leave them behind. Now you just assume they will know exactly where you are all the time with no need for Locate Soul to be casted.
This is pretty horrible, to be honest. These all also work on the PVE side of the story, so there might be a lot of people cheating their way there as well.