Whoah How Cool Are These Fights Guys instead of what the original did, which was show the deep emotional impact of being the last person of a dead culture in the ruin of their society.

Genuinely some of the greatest writing advice I've ever heard in my life: "Nobody gives a shit about the events in your story. They care about how it affects the characters."

Thousands of nameless extras dying in a slaughter is essentially a statistic. What gives it meaning is how it impacts Aangs development and having the audience learn about it and see it through his eyes defacto makes them empathize with him more.