So, I've been playing Pokemon Y for a while now. I'm now at the part where I can learn Hydro Cannon for Greninja if I so choose. Right now, I have a Hardy Torrent Greninja with Hydro Pump, Waterfall, Acrobatics, and Return. I'm wondering whether I should replace Hydro Pump with Hydro Cannon for higher OHKO potential. I know it has a recoil turn, but if you KO a Pokemon with it you can simply switch out. And Hydro Pump's BP has been reduced to 110. So what should I do?
Your better to stick with Hydro Pump or another STAB move for Pokemon to counter Pokemon with sturdy. Overall scald is the best STAB move for greninja in competitive play, for in-game play surf is useful and effective. If you greninja is short on power theres plenty of ways to improve it, look on the moveset section of Pokebase