I am just starting to get into competitive and watch tournaments to learn so I'll admit that my word shouldn't really carry any wait. But from what I've seen banning something that is being used very commonly in a tier just causes another problem to arise. If Haunter is banned to OU it won't be used there at most it would be a gimmick rarely seen. Another threat would surely come to take its place surely not as powerful, but causing problems just the same.