I'm pretty sure that if you use major creatures instead of minor creatures with animal kinship, you are using animal kinship wrong.
There didn't used to be much choice for some creature types, but there is now for most (not all).
If the point of your book is to spam kinship bonuses, I agree with you. If your point is to play it as a late game card when it does something useful, and ignore it when it doesn't fit, then that can work too. In my experience Kinship is played for an undispellable Elusive trait, with a bunch of side-bonuses when you are lucky. It's okay in that role.
Spamming a bunch of minor creatures is okay as long as they are good creatures, and what you want to play anyway. Playing sub-optimal creatures to work with kinship is a false economy in my view.