These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Emperor Daibazaal, the ruler of the Galran Empire, is a despotic conqueror, slaver and murderer. Seeking to expand his grasp across the Galaxy, Daibazaal conquers planets that will submit and destroys those that will not. The slaves taken are condemned to fight in gladiator arenas, or fed to the monsters on planet Galra for his amusement. Daibazaal has no hesitation at taking attractive slave women as concubines. One that he once favored once begged him to give better treatment to the slaves, for which he strangled her to death. Daibazaal and his son Sincline have a mutual loathing of one another and Daibazaal has no compunction trying to get him killed. Brutal, nasty, smug and cruel, Daibazaal is an example of an Evil Overlord at his worst
Prince Sincline, Daibazaal's son, and eventual leader of the Galran armies is introduced presenting his father with the severed heads of the leaders of worlds he had conquered. Sincline spearheads the invasion against the planet Altea, guarded by the robot GoLion and its five pilots. Initially honorable and chivalrous, Sincline reveals his true colors when he cheats in single combat and develops a fascination with Princess Fala, one of the pilots. His obsession carries over to abducting her cousin, Princess Amue, who resembles her greatly and abusing (possibly raping) her. Sincline is notorious for his rage at subordinates and failure is usually met with swift and painful death. With no loyalty to his father, Sincline tries to assassinate him, before pulling a successful coup where he forces Daibazaal to fight the heroes with the promise he'll be restored to the throne if he wins. Naturally, Sincline sabotages his father and lets Daibazaal die before hemming in GoLion with innocent prisoners in exploding capsules. When Galra is besieged, the new King Sincline slaughters his own subordinates who wish to surrender and has no compunction trying to kill Princess Amue. When his grandmother, Daibazaal's mother and adviser Witch Honerva opposes him in grief over Daibazaal's death, Sincline viciously kills her. He later takes a hostage to ensure his escape from Galra and tries to kill the heroes with a bombardment, declaring that as long as he lives, Galra.
Fair for Its Day: In the 1980's, it was rare for a female character to have an active role as a main character in a shonen, especially if she wasn't a love interest for The Hero. Not only did Fala have a platonic relationship with Akira, but she also had no set pairings with any of the other men. As a main character, she was one of the pilots for Golion, learned Judo, used swords and guns and even had the chance to save the day every now and then. Despite being an occasional Faux Action Girl, for Golion's time, she would have been considered quite the Badass.
GoLion Is Big In America: Voltron is far better known in America than GoLion is in Japan. In fact, GoLion is almost forgotten there. This is because when GoLion premiered in Japan, there were already tons of transforming/combining mecha shows on the airwaves, while in America it was the only show of its kind (and it had to compete with Super Sentai in Japan too, which, aside from a Gag Dub of Dynaman on Night Flight, America didn't get until the early 90s).
Tear Jerker: The death of the Gorgon beastman who adopted Shorty.
The destruction of Earth
Shirogane's death doesn't get a mention? Then of course his brother's death.