Wrangler is literally retarded, any halfway decent engineer can be pretty unkillable with it and it makes mini-sentries that much more annoying and level 3s potentially devastating. And any halfway idiot engineer can use it to some beneficial extent because the damn thing has auto-aim and you can just hide behind its shield and never take damage if the team isn't being properly aggressive.
It's absolutely 100% my least favorite thing about Highlander, though a lot of the rest of the whitelist can be almost as annoying or manages to make the game unfun. Hell, it's not even fun to deal with in pubs.
I'd like to know why people like it or think that it is actually fun to play with other than suggesting some magical improvement to engineer quality of life. Cause yeah, a weapon with auto-aim just makes the experience so much more magical and all. It typically doesn't even change the fact that an uber is going to take out the gun, unless positioning or airblast spam is the key there. It's just... ugh.