WELL. yeah usually cats are weak that's why we loose them a lot. it's part of the game . when u have a only mounted wars also be prepared to loose many. With canons it's completely different for example. I just had a game where i rushed with them and some knights and muskets - 5 wars - lost one or two canons. Before capitulating the last ai i was wih full health canons. It really depends what's on the other side. if the ai have had Cuirs or Cavalry then i would loose a lot but they are not defenders so again not very dangerous and again it's doable to take a city full of mounted.