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.
Draco in Leather Pants: Lotor is so very, very much this. It doesn't help that a lot of his worst acts were edited out, or being shown as being in love with the princesses instead of being attracted to them because of their resemblance to his mother.
Even less helped by the purely original third season of the show, which has him become much more of a conflicted character, rather than the straight-up villain he was in the Golion-adapted first season.
Fan Preferred Pairing: While the Canon Keith/Allura pairing has a LOT of fans, an almost equal number of fans like to pair Allura with Lotor, in part because of Lotor's Draco in Leather Pants vibes, and in part of scrub off some of the Purity Sue aspects of Allura.
Get On With It Already: The titular character doesn't show up (except in flashbacks) until the end of episode four, and getting the story to that point is agonizingly slow at times.
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 the show premiered in Japan, there were already tons of transforming/combining mecha shows on airwaves, while in America it was pretty much the only show of its kind (not to mention it had to compete with Super Sentai in Japan too, which America didn't get until the early 90s with Power Rangers).
Also, Vehicle Voltron is better remembered in Russia than in America because it was shown there first.
Macekre: Played straight in terms of some of the plot, like making the villains somewhat more one-dimensional, or in terms of Lull Destruction (holy cow the Lull Destruction). However, Voltron also subverts the trope; most people consider the show a "good" Macekre in that while the changes were vast, they were chiefly done so that the show would even be airable in the US, and the edits didn't remove what made the show fun in the first place (e.g., people in combining robot lions having one Big Damn Heroes moment after another).
Narm: Just watch this video of some of the best moments of the show and wonder if anyone had a straight face while recording their dialogue.
Seinfeld Is Unfunny: Yikes, it can be hard to understand why anyone ever liked this show, when a modern viewer sees it. The Lull Destruction, the Stock Footage combining sequences, the formulaic episodes... it's worth remembering that Voltron really was bigger than the Transformers at one point, though.
Although Allura is the last of the royal family, so they aren't totally unreasonable to not want her to fly. A better case would be when Nanny volunteers to scout recruits; she puts an emphasis on having a man pilot the Blue Lion.
Woolseyism: Sven ought to be the Woolseyism poster child.
To detail: in GoLion Shirogane, the character that would become "Sven" was killed off early on so that Fala could become a pilot. However, the Japanese rather liked the character and wanted him to return, so GoLion has his twin brother show up at the end of the series, which ends up feeling a little ham-fisted and awkward. World Events Productions, on the other hand, had a "never say die" policy at the time; to get around this, they rewrote the script: Sven was taken off-world to receive medical attention from an attack on his life. So when the time came for Shirogane's brother to show up, they just brought Sven back. Many fans, in both the US and Japan, prefer this change.
Macekre: The entire nature of the conflict between the Galaxy Alliance and the Drule Empire was changed. Also, of course, being forced into the same universe as Lion Voltron.
The Galaxy Alliance was only in this show, and called the Terran League.
Pidge and Chip were not brothers in the originals, since the two shows were completely unconnected.