Side Note: Nen is overrated bullshit, a complex explanation does not mean something is good. It was bullshit from the moment a second rate fighter like Kurapika could defeat a spider because he had 'conditions'. Gon randomly powering up with friendship and then got his powers back through a wish. GTFO.
Regarding Nen, you're being disingenuous. Nen has always been built around risk and sacrifice. The more restrictive a condition is and the greater the danger involved, the greater the power it can provide. We've seen plenty of characters use conditions, but very few are willing to stake their actual lives on them. So I think it's fair that someone willing to take that kind of risk receives a greater reward than someone using relatively minor conditions. Kurapika's conditions are specifically tailored for the Spiders, so in my opinion, it's fair. He can defeat them, yes, but his most restrictive abilities only work against them. If he uses them on Tserriednich or anyone else, even fodder, he'll die. And Emperor Time is literally shortening his lifespan every time he uses it. Heavy use of it can cause him to fall unconscious and sleep for hours, which consequently costs him even more of his lifespan. He's already lost a year or more on the ship without even fighting.
funny that you're using Kurapika and Gon, the only two characters we know of who have made sacrifices on that level. When you're literally putting your life or your entire future on the line, expecting a massive power increase is hardly unreasonable
As for Gon, he sacrificed his future potential to obtain that power. Sure, Nanika healing him is convenient, but it's not like Gon was dead in the first place. He was in extremely critical condition for more than a week, and Killua had to go through hell just to get Nanika to him, putting his own family at risk in the process. Luffy, meanwhile, literally died twice and resurrected himself mid-fight. I haven't even seen something like that in Dragon Ball. Gon survived, but he lost access to Nen and essentially has to start over. He is still paying for what he did. It's like Luffy losing his
fruit and
Haki after using
Gear 5 against Kaido
Even Ging tells him to be content with what he has, implying that wanting his old power back would be greedy.
Gon's transformation was basically a glimpse of what he could become after more than a decade of relentless training, according to Killua. Judging by the direction of the story, he ain't reaching that level again.