In the time since this game has come out, there has only been one new pet. i dont know the difficulty in making more but it would be nice to have some more pets available. A good example would be raptors or griffons. They are in the environment and i could see them being good pets as well. Also it seems animals dont have much differences in stats if they are in the same category. In this instance, it would be nice to pick a fern hound over a jaguar because one has more power or vitality than the other. Instead, it seems like your just choosing a different skin for the same animal.
An idea to maybe help fix this would be items for animals. A collar for a dog to increase toughness, a fish for a bear to increase power, etc.
These are my outlooks on making rangers a little more exciting.
More pets and more variability
I like these ideas. They would bring some originality to the pets.