Personally I don't mind that they're chance items or the price of them. I'm only annoyed because I want 5 of them and in 10 spins, I didn't get any. Though I have taken a liking to my baby cheetah/leopard thing which I didn't want initially xD Just don't do this with minions, k? ;-;
Rotating stock could have been cool, and might have solved the issues presented in this thread.
Release ~25 animals in the chance machine, and then rotate the stock every few weeks. It would be less of a gamble to get what you want (if it's in stock), but it might take some time for that item to come back, so you have to weigh your options.

I like this idea iff theres a couple people who are going to blow tons of csc to get some for themselves and put some on the market in addition to the regular try 10 times and not get what you want people. IF it doesnt do that, then it probably would have been better to charge more and not be chance. But whatever makes subeta more csc is best :P.
I think having it as a chance machine is fine, and although the price seemed a tad high at first, people were trading them and what not, so even if you didn't get what you wanted you could still trade somebody for it.
I think having more like this would be cool, with birds(harpy eagles, birds of paradise, secretary bird, mandarin duck, etc.) and fish(so many fish! And I'd have to get them all for a TC xD) and maybe rainforest animals or desert animals or tundra or mountains or anything really(I'd love a coati, though; unless we already have one that I don't know about). :D
Oooh, and mythological animals too! Not just unicorns or dragons, but kelpies, cactus cats and splintercats(ok I'm biased on those two), tanuki, hippocampus, bakeneko, hydras and plenty of others.