This is Potter's simplest book and is aimed at the youngest readers she ever wrote to. It tells a simple moral tale about the difference between a bad rabbit and a good rabbit. It is aimed at roughly three year old children.
I don't think that you could get away with this book today because of the violence and raw emotion of the book. It is really a wonderful book because it has content and emotion and plot and Potter's beautiful illustrations.
It is the best book I know aimed at very young children and we shall not see its like again.