I think the biggest issue is Joker somehow getting on the island. It may have been better if he confronted WW in Man's World.
But then, Cheetah even getting inside the Fortress is also some nonsense, so whatever.
I will always love classic BTAS Harley and consider her the best character to come out of DC in the 90s, but yes the current...thing they publish and call Harley is not good.