I think a reference to Earth would add a much-needed touch of humor to the film.
Maybe we could have a party (Gathering of dignitaries, perhaps? Maybe include one-shots such as Stratos and Buzz-Off? MOTU IS supposed to be epic now, isn't it?)
It doesn't have to be anything MAJOR:
Teela: His and Her Highnesses are hosting a Royal ball.
MAA: That's nice.
Teela: There's going to be an informal event the day before. Something The Queen calls a ... "barbecue".
MAA: A ... "barbecue".
Teela: You know ... a party. The Queen tells me her family had them all the time ... back on Earth.
MAA: What do they serve at these ... barbecues?
Teela: Steaks ... ground meat things called "hamburgers" and "cheeseburgers" ... and something called "hot dogs".
MAA (shaking his head, bemused): Her Highness and her Terran customs.
Seriously, Queen Marlena could be Eternia's own Barbara Bush!
Seriously, do we REALLY want two hours of action, action, action without any character development? You might as well get Michael Bay or Uwe Boll to direct.