There are 2 things. There is making something canon a realistic, and then there is making it so canon and so realistic that you are nerfing it a TON. Yes being canon and being realistic to the show is important but not to the point you are nerfing the move (I AM NOT SAYING YOU CAN'T NERF MOVES). "Yes why not, that would be more abit challenging and realistic.", its not about making it challenging, this is an advantage that waterbenders have. If you are a waterbender on land, you mainly depend on plants and or bottles. If you nerf that, it would be like nerfing the amount of mobility airbenders have. There are special advantages that all the elements have that if they are nerfed, even if its tiny, it can effect it to the point that it is useless. For examples: Firebenders can use lightning on watercampers. If you nerf it so that lightning on water does less damage or has less of a chance to paralyze, its making it useless. Earthbenders have the power to have earthbendable blocks in their inventory, place them, and earthbend them. If you nerf it so that the amount of earth around you predicts the amount of damage you do with that one earth block, its making it useless. Airbenders have the power to attack people and deal alot of damage without being hit due to how fast they can move both on the ground and air. If you nerf it so that airbenders have some sort of exhaust to shorten their speed, take fall damage, or decrease the amount of knockback airblast does to yourself, it would make it useless. All of this is the same with waterbenders. Waterbenders have the option to take water bottles and or plants into battle in a place that there is no water so they can attack and or defend themselves. If you nerf it so that the amount of plants or bottles you have is the amount of damage and the size of the waterbending move you are doing, it would make it useless. And I like it how you are picking on waterbenders even though there are more OP threats benders can do out there (please do not ask me to list them).