It is outclassed.
Why use Pangoro when you can use Conkeldurr? It has better Attack, HP and Defenses, and Guts makes opponents think twice about burning it. Typing makes Pangoro immune to Psychic, but gives it a nasty weakness to Fairy.
Even with Mold Breaker Fighting type moves won't hit Aegislash, and in Shield Form it can take a non STAB Earthquake and retaliate back with Sacred Sword. You're in even bigger trouble if it is Weakness Policy.
Power-Up Punch and Sky Uppercut are OK, I guess. Parting Shot isn't really useful. Even with CS, Pangoro is still outsped by the faster Pokés of X and Y. You protected yourself from Brave Bird. Yay. Now what? Talonflame's just going to use BB again.
So overall, Pangoro just isn't really viable in X and Y Wi-Fi battles, but it does OK in the lower tiers on Showdown.