I also thought Pyroar was overhyped, but the more I got to using it, the more I realized that it's more than a cheap gimmick.
Here are some of the most common things people use to beat Kangaskhan:
- Ghosts (Aegislash, Trevenant, Gourgeist)
- Intimidate (Salamence, Mawile)
- Bulky steel types...