Wouldn't that be speciest though ? Not attacking you or anything, but it seems your saying the idea is it's better for prey animals to adapt to live sans predation, rather than predators eat prey.
The scenario you present involves rebuilding predator populations- meaning they don't currently exist. Is it really speciesist to value a deer's life over a potential wolf's life?
But I won't avoid the crux of your argument. Yes, I think a hypothetical world without predators would be a better place. For a number of reasons I'm not about to advocate killing off predators, but I also don't want to see new ones introduced. It may very well be speciesist, but I can't defend the alternative (an endless cycle of violent culling) without appealing to nature, so I don't.
Aside from that, herbivores commonly fight and battle with one another for mates, territory and resources. Elephants and chimpanzees are an example.
Why is it more moral for herbivores to fight and kill one another (natural selection) than it is for carnivores to eat other animals?
Violence and suffering will always exist. That doesn't mean we shouldn't do our part in minimizing it when the opportunity presents itself.