Apart from the fact that they wouldn't say anything (because generally animals can't speak our languages ;)), nature can be pretty bloody brutal. There are plenty of situations in which our species' existence has made the lives of other animals much better than they would otherwise be. I'm thinking of veterinary clinics that often perform work on wild animals, pets that don't have to be worried about predation, that kind of thing. Also I think there are probably a lot of species that have done alright for themselves since humans showed up, animals like crows and the equivalents in their niche around the world seem to do quite well in urban environments.

As someone who cares about animal suffering, is sympathetic to vegetarianism and veganism, and even somewhat sympathetic to more radical ideas like eradicating the world's predators, I think that humanity represents a very real possibility to decrease suffering including animal suffering in the world, especially as we grow in our ability to shape the world in the way we choose. Certainly, I think that humanity's existence provides real hope in this direction, remembering that the alternative is for animals to continue to suffer on nature's whims perhaps indefinitely, rather than ours perhaps temporarily.

Ask any other living species on Earth and they will say their life would be better without humans around.

Let's ask a cockroach, a tapeworm, and a decorative-breed dog :-)

Humans are leading to the extinction of many species. Given the sorts of things that happen to them in the wild, this may be an improvement.

This is too distant from the original argument to be an argument for it. I'm just playing devil's advocate recursively.