@Mr.:
This is such a good statement to make, but the fandom at large ignores the LGBT issues present in the series. The situations concerning Alluka and Kalluto should be fairly obvious, as well as Killua's feelings towards Gon.
After Togashi's other series Yu Yu Hakusho was cancelled, he made a remark stating how Itsuki was one of his favorite characters and how he wished to be able to explore the psyche of him. Both Killua and Gon somewhat take after Itsuki and Sensui in terms of the former's attraction and the latter's descent into darkness.
I re-read YYH last week, I can see how there are the similarities. Total devotion/love with a hint of madness and the desire to give everything for the other, even if the wants are not healthy.
I can sorta see where people may think Naruto and Sasuke were similar but it was very much one sided and I don't feel executed in a way that made it seem like Naruto's obsession is justified. Sasuke was an ass that barely acknowledged Naruto, Naruto saw him as a rival…then a brother for some reason. Sasuke is extremely selfish, and Naruto is blind.
We had that rescue arc between the two which is probably the bigger link. But Sasuke didn't want to go back. Killua did.
Gon was selfish in his rage, but he would generally do things Killua would do for him. But they are both sort of learning from each other as they go. You can see a progression. Some say Killua was too sudden in his blood thirsty change, but I feel that it wasn't the case, since he stated he didn't want to be an assassin. It's hard to drop trained habits though.