No one has mentioned Hidden Power yet. I think breeding for HP is to complicated and time consuming. And If the HP need changes, as it does with the meta-game, you have to breed a whole new mon = Powersaves motivation.
I suggest an Ability Capsule like item that changes HP to the chosen type.
Another idea, harder to implement, just ignoring IVs at Nationals and Worlds. Only Nature, Ability, and Moves of a Pokemon would matter. With synchronize, you have a 50/50 chance of getting the one you want. How this would happen IDK. It is not a fun idea, but it would discourage cheating.
Another small problem is when Legendaries have multiple forms - each needing a different nature, but you can only catch one. . Not a big problem, but there ya go.
I suggest an Ability Capsule like item that changes HP to the chosen type.
Another idea, harder to implement, just ignoring IVs at Nationals and Worlds. Only Nature, Ability, and Moves of a Pokemon would matter. With synchronize, you have a 50/50 chance of getting the one you want. How this would happen IDK. It is not a fun idea, but it would discourage cheating.
Another small problem is when Legendaries have multiple forms - each needing a different nature, but you can only catch one. . Not a big problem, but there ya go.