TLDR; Kings Canyon was just more fun to fight in overall, Worlds Edge has too many areas that directly inconvenience fights.
Now don't get me wrong, I actually like worlds edge, but at the same time I think it has some issues. I'm going to go into what Worlds Edge does right before I start criticizing to try and give it a fair shake. That being said, the list of things Worlds Edge does better than Kings Canyon is quite short.
You can't compliment Worlds Edge without mentioning that it almost undeniably is a prettier map than Kings Canyon. Lots more color, lots more variation in environments, some cool new building types. Its just a bit more pleasant to look at than kings canyon. But that's about it really. Yeah there are some fun little additions like the train and the vaults but in the grand scheme of things the only improvement made by switching to Worlds edge is the aesthetic. Now lets get into where Worlds Edge struggles.
My main point is largely anecdotal but hear me out. I enjoyed fighting on just about every square inch of kings canyon. Of course I wouldn't take every fight everywhere because positioning and timing are important, but any time I was in a fight I never thought to myself "I hate fighting here". Worlds edge on the other hand, has so many areas that are just an absolute pain in the ass to fight in. I hate all of the tunnels because they are way too dark so muzzle flash fills 80% of your screen. I hate certain parts of sorting factory because there are a few unclimbable ledges that should be climbable that are in key spots for when you're fighting people on the roof. I hate final fights in train yard because teams with pathfinders always just camp the high up containers with sniper rifles. Stuff like this makes me feel like the map was a bit rushed an has been left unpolished. I could list more issues like this but I don't want to be here forever. The point is I never disliked fights in Kings Canyon because of where they were taking place, and because Worlds Edge does have areas like this, I generally feel much more limited in where I can/should rotate to.
I think I'm not the only person who feels this way. There are certain areas that people just rarely go to, and certain areas where people usually just run from a fight until they're away from said areas. The tunnels are a perfect example of this. Most people only go into the tunnels for the vaults, or because they need to to get to the circle. 90% of the fights I've had in the tunnel end up at one end of the tunnel or the other rather than taking place fully inside the tunnel. Why? Because pretty much no one likes fighting in a confined space where they are being blinded by muzzle flash and can be easily grenaded, so one squad or the other will almost always pull back to the mouth of the tunnels and take the fight there instead.
Maybe this is all weird and nitpicky, but I just feel like you should generally feel about the same level of comfort and capability in every area you fight in. Like I said initially, I don't dislike worlds edge as whole, but holy crap does it feel so much more restrictive than Kings Canyon. Any thoughts or additions to these criticisms are much appreciated.
Edit: Please don't downvote if you're not even going to take the time to express why you disagree
Edit 2: so many pointless downvotes. I bet most of you just read the title and downvoted. "They hated jesus because he told them the truth"