Overall, Kakuna hasn't changed much from last gen. Poison Sting and String Shot come from Weedle, it's pre-evolution. Poison Sting is still it's main way of dealing damage, with the nice added effect of poison. Poison Sting is still considered a physical attack, so nothing has changed concerning that. Harden keeps it's defenses up, making it more of a tank, and makes it better able to take the now physical Flame Wheel, Fire Punch, and the new Fire Fang. String Shot has probably been hit the hardest, however. With the introduction of Trick Room, Lowering your opponents speed runs the risk of being more of a hindrance. However, I think String Shot could see a better use in 2 Vs. 2. Have Kakuna's teammate set up Trick Room then String Shot said teammate once or twice until Trick Room Kicks in. Once it activates, you'll both be going faster than whatever's out there, except for maybe Shuckle or Trapinch.