Here's something to consider: HxH is a long running series that takes breaks often. Most people here probably binged it in a short amount of time, so anything that's explained twice seems redundant. But HxH has been acquiring new fans since the 90's, and not all of those fans could always watch/read one iteration from the beginning in a weekend. Because of that some things need to be reiterated, the terminology and mechanics of nen alone are complex enough that it's beyond a new reader to infer everything correctly on their own. Shonen Jump is a manga for young boys, there's another one born every minute, it's worth while being accessible to new readers when your readers are new to the world.
This thinking really flies over a lot of people's head. Most notably during the exposition in the Hisoka vs Chrollo fight. The hyper consuming anons of /a/ didn't get why they were doing so much talking and explaining what was about to happen, forgetting entirely the manga hadn't had an issue in over a year and this was for the benefit of new readers or readers that needed a refresher.
As for economy of character, I can't agree or disagree. Who knows how long the manga will go on for? Saying someone like Wing is just a plot device can't be confirmed or denied when our view of HxH is still truncated. Bringing up Biscuit though makes little since since she's currently on the boat, so is Kurapika's teacher and a lot of other characters who might have otherwise been one offs.
And, just my two cents, "Show, don't tell" is the biggest meme phrase wannabe writers and critics need to neck themselves for using. There are no rules in art, least of all rules of thumb, and taking things to holistic extremes helps no one. It's underpinnings haven't stopped HxH from being a damn fine series with a great story.