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.
YMMV: Yu-Gi-Oh! ARC-V
Anti-Climax Boss: Hell Armageddon, appearance-wise. It has an awesome effect, but looks like an evil Optimus Prime with no limbs and a crystal main body.
While it's practically a series tradition at this point, some fans were not impressed by Yuya's ability to Pendulum Summon coming completely out of nowhere.
However, as Episodes 2 and 3 show, this is treated as an Ass Pull in-universe as well. Whilst everyone was at first drawn to Yuya's Pendulum Summon due to Rule of Cool, their discovering of how he did it in the first place caused them to have the exact same reaction as some of the fans. Even the officials who oversaw the tournament were shocked that something like this could happen at all. Also, Yuya himself doesn't know how the Summon method itself works, and it took him 291 duels just to Pendulum Summon a second time.
The Action Cards are basically this, allowing duelists to just pull trap and spell cards just out of their asses to prolong the duel, and often have no foreshadowing. These however, are Justified in story, but from a writing perspective, can come off as this.
Base Breaker: Sora, you'll either find him an amusing character, or be irritated with him for being a far more obnoxious expy of Rua/Leo.
Crazy Awesome: Yuya, who rides around the battlefield on cartoon circus animals and is shown running right into Solid Vision giant sweets to find his Action Cards is either this, or too silly to take seriously.
Ear Worm: The opening theme song, "Believe x Believe", full stop.
Ensemble Dark Horse: Masumi Kotsu, the LDS Fusion specialist, for being the nicest of the trio, and her straightforward personality. The Gem Knights popularity also factors in.
Family-Unfriendly Aesop: The advice Yuya's father gave him to "laugh if he feels like crying" can be seen as borderline self-destructive, especially considering the effect his Disappeared Dad status had on the poor kid. It seems like this is intentional though, as when we get to see Yuya following this advice for the first time when he starts to tear up upon the destruction of Odd-Eyes in his Duel with Sora, his laughter sounds disturbingly fake, complete with a borderline Slasher Smile.
Yuya's pendulum being yetanother pendant with mystical powers received this reaction from some fans.
Having another care-free and silly character after just coming off of one also garnered disdain. Compared to Yuma though, Yuya is more toned down in terms of hyperactivity, and he's a HUGE Stepford Smiler, more so than Yuma. In terms of personality, he's really more like a more serious version of Season 1 Jaden.
Memetic Molester: Nico Smiley the Clown Hitler has become this in fan-art due to his creepy appearance and persona. Though in canon he has not done anything that odd.
Shingo getting "nearly" skewered, regardless how bad he was acting, invoked some nasty imagery. It seemed like he wasn't expecting that to hurt when it did.
How about Hokuto's Sanity Slippage near the end of episode 9? He rains down freakin' meteors to kill Yuya when Yuya just does 500 damage to him while he still has all 4000 life points. Not to mention the nightmarish close up on Hokuto's face and the fact that this came out of nowhere since up to this point he was in control of the Duel, and just an arrogant jerk.
The Scrappy: Futoshi is largely disliked for pretty much doing nothing except getting "shivers" whenever something that he thinks is awesome happens. His body motions do not help...