What would have been a cool alternative in Korra: if the mechanist’s last name (in ATLAB who had a paraplegic son, Teo) was Sato. He would die soon after the end of the war. While Aang rebuilds, Teo wonders why Aang couldnt’d help someone who helped him. Teo moves to Republic city and lives a meager life, spending all his time working on inventions. Teo goes on to invent the Satomobile, (his background in his/his father’s inventions would create an established credibility) his piece in the puzzle would be even more complex than Hiroshi’s because of how he helped team avatar in the past. This would make the audience wonder how he did a 180 to aiding the Equalists and they would want him to realize how he helped in the past and change instead of just dying. It also gives his daughter, Asami, more of a reason to want to team up with the new Avatar and restore her family’s name by helping Korra.
I find this alternative to have much more depth the audience can enjoy from the past.