Umby
I'm gonna bury you in the ground~
Adding another slash would be fine (it's Gengar, he's THAT versatile and everyone should know it). It's just that you wouldn't be using Taunt without WoW or Destiny Bond, so you'd have to comment on that. I personally hold an opinion that Taunt + WoW serves a more defensive function, however, so adding another set MIGHT be a viable option. The former options is safer and simpler.