I feel like this post presupposes similarities between franchises and then works to justify that idea, sometimes with quite forced leaps of logic. Just because elements can technically be compared doesn't make them similar.
Regarding storytelling, the games' styles are almost diametrically opposed, even if MGS does include environmental storytelling to some degree. The points included in this section were also not entirely correct; Dark Souls fills in a lot of history and world building through item descriptions and world building, but the actual present story as well as the basic context behind it (i.e. explanations for the state of the world) occur through cutscenes and dialogue from NPCs like the knight at the asylum, the crestfallen warrior, Frampt, Gwynevere, and Kaathe.
Comparing the franchises on the basis that both were something new but followed some basic ideas explored in other games is a fairly simplistic way of looking at things, in my opinion. You can make this point about almost anything original.
The comparison between the poorly received sophomore efforts seems very loose as well. Metal Gear Solid 2 was not actually Kojima's second game in the franchise, as you mention he had already worked on the Metal Gear games before the Solid games. And while MGS2 has been reevaluated after a somewhat divisive launch, Dark Souls II's scattershot design decisions have not been in any such way. I say this as someone who has beaten the game many times and enjoys it: DS2 fixes, changes and breaks things seemingly at random, and it doesn't feel like the same sort of cohesive work of art as its predecessor. The world design is still nonsensical. The encounter design still focuses on a ridiculous number of enemies to the detriment of tactical gameplay. The original vision for the game's lighting shown in trailers was still gutted, leaving behind only hideous repeating textures that were meant to be hidden.
A few changes from Dark Souls II might have carried over, as you mention, but it's also worth mentioning that the third game in the series calls back to the first almost to the exclusion of the second.