Such as hunters are paid exorbitant amounts of money and do whatever they want, but at the same time they do fucking nothing.
And the threshold to be a hunter is incredibly low, you would expect more people to be a hunter, but no.
Think about the arena, most people at the higher floors would pass the exam with their eyes closed.
But only a few hunters exist?
Having a power system based on tradeoff except some people don't have any tradeoff is silly imho.
A power system is cool if everyone has the same limitations but different. Specialists just do whatever they want.
Hope this answer is clear enough.
Other stuff that has no logic is the existence of chimera ants that can just become Gods overnight.
Or again the fact that Hunter organisation exist.
Imo this has to be seen as hunters are composed of all kinds of people: some do the exam only for money and when they get the hunter license they simply live in luxury for the rest if their lives or simply sell the hunter license to get tons upon tons of money, yet not everybody is looking for money (or at least not only, mainly, that) as the hunter license gave you access to places and infos you can't get anywhere else. To make an example Illumi (the creepy brother of Killua) get the hunter license (first arc, the hunter exam) just because he needed the perks of the hunter license to do a job (if I remember correctly even the fatass brother of Killua pondered about getting a license in order to do some stuff).
Then the threshold is low but relatively low, a normal human can't get it but somebody with nen powers (coupled with a superhuman body and maybe mind) can do it. But actually you don't need to be an hunter in order to get tons of money, the guys in the heavenly arena for sure are loaded with money, the lower floors have huge money rewards while the upper ones just give honor as reward, that means that everybody up there is a battle maniac (and not for nothing we get Hisoka and Chrollo as veterans of thay place), guys only interested in money are shown as lame and weak willed throughout the manga (for example there were the 3 crippled arena fighters who wanted to bully Gon and Killua when they first arrived at the arena, they wanted to do that in order to get victory points, become a floor master and indeed live a life of luxury).
Some of the strongest people in the verse are not hunters, not care to become one, and are loaded with money (and still don't care a bit about it) like the spiders or the Zoldicks. You can say that actually they both seek money (the spiders are thieves while the Zoldicks get paid big money for their assassination job) yet the truth is that both "teams" seek adventure like in any shounen (why risk your life to go after chimeras, Chrollo, Kuratas etc. when you already have all the money you possibly will ever need?).
About the chimera they were overpowered like hell and even their powers were unfair but that is completely fine in my book as long as it is the enemy that gets it (and as long as the MC doesn't beat them with a "friendship punch" or some other fairy tale s***). Then of course Togashi is human and since he invented a really complicated manga (and it is part of its charisma as a manga) it is bound to have mistakes, plot holes etc. but imo HxH is not bad at all in this regard (then of course everybody has its point of view).