If Araki wrote HxH ... The story would've started with Ging's adventures, then Gon's, and then the story of the Freecs family would've continued for generations.
If Kazuki Takahashi wrote HxH ... The story would've became all about the Greed Island game after the Greed Island arc.
If Oda wrote HxH ... Nen wouldn't be as amazing as it is. Powers and abilities would either be attributed to being superhuman or magic fruits or something.
If Toriyama wrote HxH ... He wouldn't remember writing it.
Oh boy. This looks fun. Let's see
If Akira Toriyama wrote Hunter x Hunter we'd see alot more of Leorio for comedic purposes. Gon would be the strongest Hunter on the planet and have to travel to other Hunter planets to meet people with strength even close to his. The Phantom Troupe would be named after Fruits. All the villians in Hunter x Hunter would look like creatures out of fairy tailes, and Hunter x Hunter overall would be alot more comedic. Also, no hiatuses as Toriyama would think of the shit as he goes along
If Kubo wrote Hunter x Hunter Gon would be a senior in high school, Kurapika would be a D-cupped girl. Killua would be a B-cupped sophomore, and Leorio would be a creepy 49 year old, old dude. Hunter x Hunter would also be written by copying arcs from all the other popular works in JUMP and tweaking them.
if Hiro (Fairy Tail creator) wrote Hunter x Hunter all the girls would be D-cupped and all the fights in Hunter x Hunter would be boring and predicable.
if Norihiro Yagi wrote Hunter x Hunter it'd be....amazing. Simply amazing. That's that best way i can describe it. Perfect in every way.
If Araki (JoJo's Bizarre Adventures) wrote Hunter X Hunter, we'd get chapters upon chapters where random nen users try to kill the main party (with almost every encounter being a near death experience). We'd have characters/abilities named after various musicians, bands and songs too.
If Oku (Gantz) wrote Hunter X Hunter, we'd have entire chapters consisting of highly detailed scenery, short dialogue, multiple large panels for slight facial expression/body language changes and exposed boobs where possible.
If Kishimoto (Naruto) wrote Hunter X Hunter, we'd have seen Gon power up and beat the Chimera Ant king and the election arc would introduce a new enemy stronger than the king. No ability is valuable unless it is flashy.
What about Akira Toriyama?
If __________ (fill name of author of anyone except Berserk here) wrote HxH , we would have a lot more chapters >"<
If Hideaki Sorachi write HXH, Gon will love slacking of at their home than go to Hunter Exam, but Some Way Gon will be there in Flashing, And Biscuit will be clinging to Gon every chapter
Honestly if someone else wrote HXH, it just wouldn't be as good, not because Togashi is some kind of impossible to surpass genius but just the topics of HXH are very difficult for anyone else to handle. GI and Ants in the hand of another author would almost certainly flop. They didn't really end satisfactorily even in HXH and they're certainly way beyond the 'Shonen solution' (e.g. main character powers up and beats everyone up). Another author probably can handle Yorknew fine. It might even be better given the average author won't waste assets like Kurapika by having him disappear in the middle of the story.
To quote something I saw in a manga bashing board. While your generic hero who is supposed to be an average guy (or even way below average) ends up turning out to be super special in other manga and thus a huge breach of reader trust, at least HXH has the foresight by telling you that Gon (and Killua and really Kurapika) are all super special from the get-go so when it needs to call in a few miraculous victory favors it's somewhat covered.
---------- Post added at 12:31 AM ---------- Previous post was at 12:03 AM ----------
Assuming that 'someone else wrote HXH' means the story still retains roughly the same worldview (e.g. you don't expect people to randomly turn into X-tails to make up for an insurmountable difference in fighting power) the difficulty of some of the major fights, especially the Ants arc, is way beyond the ability of most authors to handle. Not even Togashi handled them satisfactorily.
Take the common Shonen Jump author, they wouldn't even be able to handle an enemy similar to Vearn's ability in Dai-no-daiboken (a character possessing the best offense, defense, magic, and is aware that all heroes must be killed immediately to prevent them from magically getting up and become 10 times stronger). That is to say it doesn't matter if you're talking about Ichigo, Luffy, Naruto, or whoever, they can't beat someone who will decapitate them as soon as they're down (and none of these guys will ever defeat anyone who is remotely powerful without being downed at least once given their characterization). Compared to this, decapititate a downed opponent is like the minimum level of combat excellence in HXH. Of course, most authors aren't really interested in writing a world with rigorous worldviews where you actually know character X will beat character Y decisively.
To even attempt to write HXH satisfactorily an author would need to show that he is capable of distinguishing the difference between 'cannot be defeated' and 'cannot be killed'. Meryem is similar to say, Dongfang Bubai in the Chinese martial arts literature. He cannot be defeated but he can definitely be killed. Of course, in most manga the main character must defeat his opponent, so there's no possible way for the average Shonen to properly resolve this, and this concept is probably beyond the ability of the average Shonen to handle.