I'm not sure if I'm misunderstanding your comment, but killing animals for pleasure alone is already largely illegal in Western countries. And that includes hunting. You aren't allowed to just hunt an animal for fun and then leave it unharvested. It is hard to enforce, obviously. But you can definitely be charged for killing deer, moose, ducks, even fish, without a license and at least the intent to eat it. For example, you can't kill a bear, cut off its paws or gall bladder, and then throw the carcass in the bush. You also can be charged for killing or treating an animal inhumanely or in a way that causes it distress. That theoretically applies to all animals, including pets, livestock, aquariums, wildlife, and even small animals like mice and bats.
Yes, there is that. I am personally against hunting because I figure wild animals are already under enough pressure from habitat destruction and climate change.
Hunting is largely cultural now and isn't needed for sustenance except in very remote places. At the same time, I'm not sure if it is fair to classify a cultural practice as being for mere pleasure. It is a bit more complicated than that. Certainly, in Canada, indigenous peoples and the descendents of early settlers think so.
Hunting is needed for wildlife management. We've killed most of the natural predators for the animals we have hunting seasons for so we need to fill that niche or those animals won't have enough food to go around during winter. I can't speak for the animals, but I would prefer being shot to death rather than starving to death. There's also the factor of more deer (and other prey animals) crossing roads being more dangerous for everyone involved.
Agreed, at least for some species like deer. I can't think of too many others, though, especially with global warming. Most of the animals that thrive despite human encroachment, like coyotes, crows, and raccoons aren't animals that we hunt.