They do seem pretty similar to our cats, based on WoJ at DragonCon 2016. Someone asked about Cats speaking Human. He said it was mostly a physical issue; cats lacked the vocal capabilities to mimic human speech, but Humans can mimic the noises that Cat make. We lack ears and a tail, so we aren't quite as articulate in Cat as we could be.
Jim owns at least 1 I think more, Maine Coons and those cats are ginormous. I'm pretty sure I remember him saying Bowie was a MC. He also has a little rescue cat that seems "tiny but fierce." I just think millenia on the world has resulted in larger cats being more common.