Well not every ninja is made to be good in every scenario. Some ninjas shine in big team battles, such as team instance and GNW. Onoki is one of those ninjas, a similar category to Hanzo. They have really great kits for large numbers of ninjas but, in a smaller 4v4 battle, they fall short of similar ninjas who do have those added debuffs and crowd controls. It isn't really a design flaw or hatred of the character it's just how the game is.