that depends on what you think are the games themes, i think a golden route would solidify it. the theme to me and many others is perspective, in every route you see how just a change of perspective paints how you see people and how the actions of one person can change everything. so like i said before the best way to do a golden route would require you to do every path to unlock it(something ive found most people wont do because "edelgard bad") and have byleth remember all the routes so they have a way and reason to change things.