Just to make you feel better. My older son's preschool teacher told me his fine motor skills haven't developed... he now at 8 years old types meticulously and loves to do cursive. He is a budding artist, and when he refused to color things or do anything as directed, I never cared. His little brother is now five and I was certain he is not going to be the artist his brother is, because until very recently he just drew messes of lines. He amazed me with the stories that he could tell me about the lines... and it was more like once a month he cared to pick up a pen. but now all of a sudden he draws and paints every day and they look amazing. but try telling him HOW to... he will have his reason why HE likes to do it THIS way. And I would not want to kill that!
If your 4 year old prefers to try to cut the actual figure instead of the lines, then good job for wanting to try harder, there's no way a normal, non prodigy child would NOT cut the tail off.