Everyone that has gone through a break up has had some type of change. Some people go on to do better than what they had and some people just keep attracting the same people.
I had a conversation with someone the other day about "emotional baggage". The damage done after a break up definitely can add to the weight of emotional baggage. Like I told my homie some people carry around their emotional baggage which leads to more heartbreak. Some people tuck their emotional baggage in the closet and only bring it out when need be. That's not the healthiest thing to do... Because it generally manifest itself in other ways such as jealousy.
But to answer your question, yes I have had a break up that changed me for the better. It allow me to find out what I want and will tolerate in a relationship.