When your opponent dodges under your hook punch, you can do at least 3 things:
1. Right back fist on top of his opponent's head.
2. Side way right elbow strike on his opponent's head.
3. Reverse head lock on his opponent's neck.
By using drop bear's term, to only train hook punch, and not to train 1, 2, 3 is "1/2 training".
By simple logic, even if elbow strike, and reverse head lock don't exist in boxing, at least the back fist should exist in boxing. There is no way that a boxer can't figure this out.