>>31173307That's how metagames work. If something is good, people will discover it sooner or later, then the metagame will shift to counter it and it won't be as good any more.
Only incredibly solid Pokémon (Tapus, Garchomp etc.) are so good that they stay strong when everybody and their mum counters them.
Worlds 2014 having no Kangaskhan was kind of an extreme case of this.