Togashi has strengths and weaknesses as a writer, of course. Certainly one of his weaknesses is that he can sometimes grow bored with his plots or characters and decide to just shift off in another direction (although at the same time, he's a good enough writer in general that the new direction is almost always an interesting one).
I think Togashi has some real strengths as a writer. He's a good ideas guy in general, with his stories often having pretty interesting world building and some striking ideas and concepts. More than any other battle shounen writer I can think of, Togashi really attempts to flesh out his antagonists to the point that they can be almost as sympathetic as the heroes (there are a few exceptions like the Greed Island villains and Elder Toguro, of course). This also ties in with his general desire to subvert tropes, but to do so in a genuine way. Unlike a lot of other writers who will do some sort of a subversion that's constantly going on about how subversive it is (for a non-anime example, see that hack Rothfuss), Hunter x Hunter feels like something that is both a love letter to the genre as well as an attempt to turn the genre tropes on their head. It happens naturally enough that you don't necessarily stop and think about it while your reading/watching. Togashi also by the latter half of Yu Yu Hakusho starts to do away with power levels as being the biggest factor in battles and mostly focuses on different unique abilities that characters posses being the bigger factor.
I think he also has a skill at sketching out basic characters pretty quickly. From early on you can get a likable and understandable portrait of characters like Yusuke, Kuwabara, Kurama, Leorio, Kurapika, etc. They might not be the deepest characters in the world, but they're all reasonably fleshed out and understandable. There's also just something to be said in general for the characters being largely all likable to watch or read about. This might seem like a low bar, but with the vast majority of series out there, a lot of people seem to dislike at least some of the characters, yet I rarely encounter very many people saying "Man, I really can't stand Yusuke" or "Kurapika is the worst, I'm glad he wasn't in this arc". What Togashi's characters might lack in terms of deep explorations of their psyche, they can make up for with just being enjoyable characters to watch who grow enough over the course of the story and get put in some interesting situations. I think Togashi also usually does a good job as time goes on about exploring the last effect that everything has on these characters. The Demon World arc in Yu Yu Hakusho is really all about how Yusuke, Hiei and Kurama no longer have a place in every day life and they have to go seeking out new fights (and one's explicitly shown to not be necessary or having a nobler end goal) to stay relevant, while Kuwabara is able to actually reintegrate with society and has the possibility of living a normal, well adjusted life. (Many fans completely miss the point of this arc and think that Togashi is disrespecting Kuwabara as not being strong enough to keep up with the other characters, when in reality the story is really about how Kuwabara is the strongest one for not having to keep fighting)
Of course, Togashi's weaknesses (even excluding punctuality or the chicken scratch drawings he puts out sometimes) certainly exist. As I mentioned above, his characters certainly aren't the deepest, although he does have a few who are pretty complex. They make up for that in other departments, I think, but it can be a weakness of his, as is his tendency to sometimes get bored with certain plot lines. Another issue, of varying degrees, is his tendency to just introduce a massive amount of side characters that never wind up going anywhere. I get that part of his intention here in Hunter x Hunter is to just sort of show the characters going through their lives, so sometimes they meet some folks who fall out of their lives pretty quickly, but it can be fairly disorienting and sometimes winds up feeling pointless. Yu Yu Hakusho, as much as I love it, was fairly aimless for most of the series, with each arc mostly just involving a new enemy for the characters to fight. The final arc does deal with this and touches on where the characters are going, but it would have been nice to have some of this earlier on. You can really feel how Togashi was just making shit up as he went along (and I think it's pretty clear that Toguro's heel turn was not planned until much closer to the end of the Dark Tournament).
I don't believe those photos were in the manga
One might have been.
There was definitely at least something in there. We knew that Killua had another younger sibling for years prior to the election arc.
