Would You be Okay With More Animals Being Introduced Using the Same Models Already In Game?

If they can get a head start for new animals by using work they already did on existing ones, sure why not.

It all depends on what kind of animal they are going for. A horse would obviously need a skeleton in a different proportion than cats or dogs and it's own animations.
But they could use cat or dog animations as a starting point (not just a downright copy!) for other animals of that size. For example wolves in a werewolf game pack would be awesome. They can definitely benefit from the dogs we have in game.

I hope we get fantastical animals like pet dragons or unicorns at some point.