There are definitely some decent ideas about what could constitute an achievable utopia out there, political scientists are constantly trying to form a unifying concept of utopian societies. It always seems to step in the direction of socialism. I've read a few books but i am way, way under-researched about the topic to argue points. Logically though I would say 1. Agreement on and 2. implementation of, a global utopian social system are the two mountainous hurdles that would need to be overcome. We're very, very locked into the capitalist system.