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: Black Adventures
And the Fandom Rejoiced: Anytime there was so much as a hint to a scene in the ferris wheel.
Broken Base: Parts of the fandom got in a tizzy when Isshu's English name was announced to be Unova. Black is just calling it New York, probably to skirt around the issue.
He was even given his own slot on a recent character popularity poll; the only other characters to have their own slots were Black and N (understandably), with Ingo and Emmet sharing another slot, being Ensemble Darkhorses from the original games.
The shiny Litwick in Episode 21 is gained a following fast enough to start the possibility of black catching her. Artist!Black is aware of this, and drew a gijinka version of it. She even has a name.
Fan Nickname: The Kami Trio contains Thundhurrus, Landorkus, and Tornadeuce.
Hilarious in Hindsight: In the story, Thundurus attacks Nimbasa City as well as the main character. In Pokémon Special, which the author is a fan of, the first doesn't happen, but the second does. It happens right after Black's gym battle against Elesa, to boot.
Ho Yay: N is pretty much openly in love with Black and Black isn't protesting too loudly.
Black seems to get quite flustered when Arti is around...
16 is the age of consent in some countries and N has the mentality of a twelve year old (okay, that may also make the whole thing worse). N definitely thinks Black is much too young to go around the world getting into danger though.
Now 22 and 17, respectively. Also, 17 is apparently the New York age of consent.
The reason it is YMMV is that while it is legal, many people find relationship age gaps that large at a young age to be distasteful, out of a notion that the younger individual is being taken advantage of. This becomes especially Squicky (though again YMMV) when one considers that N started out as being Black's Stalker with a Crush and emotionally manipulated him into their current quasi-relationship.
Unfortunate Implications: See Squick above. Also N is almost literally a Stalker with a Crush whose relationship with Black is pretty emotionally and physically abusive to him.
Villain Ball: Barring the argument of Happiness in Slavery, Team Plasma's actions make even less sense in a universe where Pokemon can talk.