Given that Harry Potter is literally the titular character in every entry in the Harry Potter series, it makes a lot of sense that he is the protagonist of the story. And as far as leading men go, Harry is certainly a good one. He is at the center of the battle against the Dark Lord Voldemort, and even putting that aside, he's a relatable and compelling character in his own right.
However, what if things were different, and the audience got to see the story from a different point of view? Namely, what would JK Rowling's famous wizarding tale be like if Neville Longbottom was the main character instead?
Should: He Offers More Insight Into The Wizarding World
One big potential upside to having Neville as the main character in the Harry Potter series is that he is already entrenched in the wizarding world from the moment he's born.
A huge aspect of what makes Harry Potter so compelling is that its world-building and mythology is fascinating, and honestly a lot of the potential for even more wizarding world development is lost due to the fact that Harry, someone who is completely unfamiliar with magic at the start, is the main character.
Shouldn't: Because He's Less Relatable For The Audience
On the flip side of that though, Harry himself makes for a good protagonist because he's someone that the audience can relate to. He grew up in the real world and is learning about the wizarding world right alongside the audience themselves.
It also plays into the fantasy that all Harry Potter fans likely had as children. The idea that someone can be living a mundane, even terrible life, and then discover that they're a super-powerful witch or wizard, is very enticing.
Should: For His Love Story With Luna
Neville Longbottom and Luna Lovegood never canonically had a relationship, although Neville did finally declare his love for Luna towards the end of the film series.
The potential for their romance was actually staggeringly popular considering the fact that it was solely based on their friendship and chemistry, but if Neville had become the main character of the story, then clearly this love story could have blossomed as well.
Shouldn't: His Involvement In The Major Storylines Comes Too Late
In terms of actual character development and evolution, there are few characters in the Harry Potter series that have a better arc or more dramatic change than Neville.
However, the fact is, he didn't really get into the thick of things until about halfway through the series. While it would be interesting to see things from his perspective in say, Half-Blood Prince, that perspective shift wouldn't work nearly as well in an entry like Sorcerer's Stone.
Should: Because His Evolution To Hero Would Be More Interesting
However, while Neville didn't get involved in the external major storylines until well into the series, his internal development as a character would have been a lot more interesting and dramatic than Harry's.
Even when Harry was just a child, he was pretty fearless and ready to throw down with the Dark Lord. Neville had to grow into his heroic role, and it would have been fascinating to see a character develop that drastically.
Shouldn't: Because He's Not Voldemort's Enemy
While Harry is the clear protagonist of the Harry Potter story, he is in large part the protagonist simply because Voldemort is the antagonist.
Ironically, Harry is the protagonist that Voldemort "chose," and that therefore makes Harry's story more interesting and relevant to the Wizarding War than Neville's is. But since Voldemort believed that Harry was the chosen one to defeat him, that makes Harry's relevance to the war against Voldemort far greater than Neville's.
Should: His Family Is More Interesting
Although it's hard to imagine a familial backstory that is as tragic as Harry's, it's hard to deny that Neville Longbottom's family dynamic would have been a lot more interesting and complex for the main character. In a certain way, Neville is an orphan just like Harry.
His parents might still be alive, but the people that they were are gone and never coming back. And, having parental figures that the main character can actually interact with offers a lot more narrative potential.
Shouldn't: He's Not Involved In The Adult Drama
Obviously the main focal point of the overall story is on the students at Hogwarts, but Harry, Hermione, and Ron's experiences at the school aren't the entire story.
Many of the adult characters like the Order of the Phoenix and the Death Eaters are a huge part of the overall saga, however, they almost never interact with Neville, so if Neville were the main character a huge portion of the story would be cut out.
Should: Because He's The Un-Chosen Chosen One
Harry Potter author JK Rowling presented a fascinating tidbit of information in the book series. While Voldemort believed that the prophecy made by Sybill Trelawney was about Harry, the contents of the prophecy could have just as easily applied to Neville.
So in theory, had Voldemort gone after Neville instead, he could have also been the "chosen one" instead. Making Neville the main character of the series would have been interesting because this idea could have been explored much further.
Shouldn't: Because It Would Require A Ton Of Exposition
While Neville Longbottom or any one of the other characters in the Harry Potter series could make an interesting protagonist in their own right, ultimately it's hard to deny that Harry as the protagonist makes things a lot easier.
He's in the thick of nearly every important event that goes on and he's familiar with every important character in the story, and if Neville were the lead character instead of him, it would require an insane amount of extra exposition.