Complex sentence: Lucas grew distracted by other projects, but he would return to complete a second draft of "The Star Wars" by January 1975; which still had some differences from the final version in the characters and relationships.
Split into simpler sentences: Lucas grew distracted by other projects, but he would return to complete a second draft of "The Star Wars" by January 1975. This second draft still had some differences from the final version in the characters and relationships.