Crobat AS/AC
Is Crobat AS/AC something to keep vs potential future fighting defenders?
At the moment there are no fighting defenders in the meta game but crobat is the only flying poison pokemon (double resistance to fighting and super effective damage with its flying attacks). It is not A rated moveset at the moment however.
Answers
The superior stats of dragonite and some psychic pokemons 'll make them probably better than crobat with its double resistance vs fighting. But the double flying moveset on crobat looks the only moveset worth having above the A rated moves (i don't see a good use for these) Air cutter doesn't look like a real good 2 bar move but we know these moves can change in the future.
And against a fighting bug like heracross it becomes even more obvious, crobats flying moves deal 1.56x damage while receiving 0.64x damage from heracross fight moves, probably here there is no better alternative (A pity heracoss is region exclusive and is virtually non existent as gym defender)