Cats are not social and don't have a hierarchy?
As somebody who has been around both dogs and cats for all of my life, I disagree 100% with your claim that dogs are more trainable than cats. The main reason that dogs are considered more trainable is that humans have been selectively breeding them for specific traits that we can then train them to perform on command. My current dog is an Anatolian Shepherd, a breed that has been bred for the specific task of protecting livestock. Not herding them. Not chasing them. Just hanging out with them and chasing away or killing any predators that come around. They traditionally work with sheep and goats but mine is protecting chickens. I was able to train him to protect these chickens because the basic protective instincts bred into his DNA. Dogs like retrievers have not been bred to protect livestock. They have been bred to grab birds and bring them back to their owners. I would probably have better luck training a cat to protect my chickens than a retriever.
Cats in our world are not bred for any specific tasks or behaviors or intelligence. When they are bred at all they are bred for appearance based traits only. 376
But as an example, it is common for mother cats to bring stunned but still alive prey like mice and squirrels back to their kittens so the kittens can learn how to pounce and hunt them. That basic behavior could be trained and bred into retrieving downed birds to their owners just like we did thousands of years ago when teaching wolves to do the same thing.
Herding livestock is really just chasing them in a controlled direction and we were able to train wolves to do it because they naturally work in packs with some dogs chasing the prey towards the other dogs that are waiting in ambush. This is nothing inherent to wolves. Any animals that hunt in groups will learn this, and lions do it very well. There are other examples of cats working in groups to hunt. Cats normally hunt alone because that is what gives them the best results. Change any parameters so that hunting in groups provides greater rewards and cats will quickly adapt to that new reality.
Humans domesticate animals that have something to offer. If wolves are not available to your early humans but some type of cats are, then there is no reason that cats could not be domesticated. And after several thousand years of controlled breeding for specific behaviors, cats could be just as varied, specialized and trainable as dogs are in our current society.
The question asks about cats and seems to pull the idea of out current domestic cats that came from small desert cats in north Africa. If I were to choose from all of the existing cat species for basic stock to begin domesticating as dog replacements I would choose the cheetah. They of all breeds show the most affinity for humans, willingness to domesticate and lack of appetite for human flesh. They also have demonstrated willingness to hunt in groups when appropriate which is a headstart for some types of roles that they would need to perform in their future domestic role. 376