I don't think we need shields. I do fine blocking and I suppose the devs wants players to defend themselves in different ways than they're used to from other games.
Simply mastering the blocking mechanic is already rewarding rather than cowering behind a 100% block shield.
I support the current blocking system, it's a nice change of what we're used to.
I doubt animals like lizard and snakes would fit, they would be enormous. I had the same idea for birds and moles but the size just won't allow. I dowm for more insects tho! Water insects, dragonflies! Can't wait for those.