Give Samurott Aura Sphere and make it Water/Fighting-type; it's a frickin' samurai otter.
Make Psychic deal neutral damage to Steel or resist (or be super effective against) Fairy.
Lower Moonblast's base power to 90.
Keep Aura Sphere and Dragon Pulse's base power at 90.
Raise Hydro Pump's accuracy to 85 or 90.
Give Blastoise a better Shiny.