In my opinion, overall it is a bad costume - but I also think that is intentional, as Wu Kong is probably the most used 4 star card across the game. Didn’t need a costume to be loved so it was made a niche one. Additionally people are disappointed because ever since the costumes started being released, Wu Kong was anticipated to become a cheap version of Tarlak. SG knows money is with Tarlak and Miki, and any future titan specialist they release. They don’t want to have a cheap substitute.
Is there a place to use him? I think rush tournaments against purple centers if you play mono (I personally always play mono on these). 210% to all with his high attack is substantial - Li Xiu’s dmg is much lower (and you take her costume to mono with this rule anyway), Dan is comparable and with blind but at 33% chance of happening only, Hu Tao has higher % but lower attack stat and his costume actually makes it even worse… So yea, Wu Kong costume will be nice aoe dmg dealer there. I am happy taking Jack O’Hare in similar circumstances against blues and his dmg is satisfactory. Wu’s should be slightly higher.