So I have to ask then what does theme mean to you? I am not trying to be rude or anything just genuinely curious. I don't see how this thematically fits whatsoever. Just because Starlord was an American does not make it thematically appropriate in my opinion especially when other members of this dance party are not American.
I'll take a shot at answering what theme means to me...
I love how each country in WSC is different - architecture, foliage, culture, food, stores. I also love how when you leave one "country" there is a natural, well thought-out barrier before arriving at another "country". The theme of each country is to give a "flavor" of that country, or part of the world, rather than actually trying to replace an actual visit to that place. Perhaps more kids have had their curiosity wetted to learn more about the scandinavian countries because of Frozen, but just being exposed to some of the buildings and performers at least has an impact, I think.
One big difference for me between Disney and Universal (other than the obvious thrill-ride vs. various types of entertainment), is theming. When you walk though Universal, you leave one "land" and immediately enter another. Not better or worse, but different.
To me, that difference at Disney is the attention to the theme of whatever area you are in - the attention to detail - the "seeing what they want you to see" rather than the background we all know it really there... the ability to be able to suspend reality and be immersed in the magic, even for a tiny slice of time.
That's theming...to me anyway.
