Short answer: I think he's neat, and that other people should think he's neat.

Long answer: Because of Marth being the first protagonist of the first game ever, and said game being released in Japan, the first exposure the West had of him was in the Super Smash Bros. series, and for me, Super Smash Bros. Brawl. I was really young then and didn't know about the Fire Emblem series at all outside of very surface level knowledge, and I had never really seen advertisements of it, since I lived in a country where accessing games meant pirating games mostly. I only got into the series due to Conquest and then Tokyo Mirage Sessions, and even in that game I mainly just... didn't care about Marth really.

Then Heroes and Warriors came out. Though the latter game had given Marth some much needed exploration, I felt that my indifference towards him was mainly due to me caring more about the Fates roster in the game at that time, and that Heroes didn't do a good job portraying him as other than 'good generic chosen one #1' at the time (the exploration potential of Heroes vs what they actually do... a rant for another time). Keep in mind that I thought Fates writing was actually good at that time, and also was never really aware of his depiction of the Shadow Dragon remake.

It was only when Engage came out that I started to care for Marth. Hhe was there in the beginning and has such a sweet relationship when he was on-screen with Alear that I couldn't help but be drawn to them and him; even with Alear's memories missing I felt like they had a natural chemistry and history between one another, and during Chapter 10 where Marth gets ring-napped, I started to joke in the place of Alear, making them say 'where Marth' until you reunite with him in Chapter 21.

I'm a weirdo who attaches to characters that have angst, and especially when it's a self-sacrificing hero who fights for what they believe in, like Marth. Looking back at his conversations in Engage as well as Warriors as well as Heroes and his home game, I can say that he's a really sweet charaacter that just wants the best for people. I love it that despite being royalty, he sees himself and his friends from all backgrounds as equals; that he tries his absolute hardest to make people happy; that he's humble, and knows that he's not that strong nor wise, but his charisma and honesty makes him an ideal, shining beacon for people to rally around for the greater good. He's endured a lot and recognises that he's not a saint, yet tries and shows mercy - killing only when absolutely necessary. I think he's the goodest Fire Emblem boy, and I hope you now share my enthusiasm towards him too!