Metal Gear Solid was one of the first games to kind of capture an audience with its cinematic styling and focus on stealth mechanics and went to great lengths to explain its narrative and try to ground and contextualize it with a backdrop of real-world geopolitics.
Since the series took a lot more strides with its layers of storytelling than its contemporaries, a lot of people -- myself included -- tended to believe that Kojima had a real prowess because of the lengths the MGS games would go to layer their world. There's undercurrents of humor that kind of lent it a zany charm that was in line with the mindset of my younger self, too.
So yeah, as the MGS games came out, I didn't think there was anything among its contemporaries that kinda put the effort into the storytelling. I'm not at all saying that all of it stands up as good today, or that the industry didn't eventually find leaner, more poignant and more effective ways to basically accomplish the same thing in storytelling (whereas the kinda technopunk elements of MGS felt more like an attempt to spice-up and add some dazzle factor to the political thrillings), but as someone who grew up a console gamer, MGS was largely unrivaled in terms of the cinematic factor and Japanese action game styling all in one package.
I've not held dearly to all of Kojima's traits as I've grown older and kinda matured into a different person than I was as I was exposed to MGS, but I do still endear to Kojima's signature style on the whole. He's not immune to being criticized in my eyes, and a lot of criticisms that have come forth about him ring as completely reasonable, but I still look forward to every Kojima game, still kinda clung to that long-running idea of him being one-of-a-kind (and it still somehow holding appeal to me).
At this point, at 32 years old now, I completely get why someone wouldn't be into Kojima or even view him as entirely overrated -- he hasn't shown a whole lot change that takes the same changes I've personally undergone, but I still can kinda shift my mindset into a realm of appreciation for the type of style he has.