This is still my favorite game of all time and I will tell you why.
I don't think it is ever going to be topped. What made it so great was not that it was a technical masterpiece but it is actually in spite of that. Its so great because it is so flawed.
I know that sounds odd but hear me out. Games keep trying to strive for perfection in their mechanics. Everybody seems to want these games with rock solid polish and despite what people think, developers are actually trying to give people what they want. The problem is no game can ever be completely perfect the more technology progresses. Games are way too complex. Human error is going to miss things despite the effort to polish games as much as they can. People seem to want these hyper realistic games with photo realistic graphics and realistic physics. This also tends to mean people just think perfect games have to be as close to realism as possible. This strive for perfection has also led to games becoming formulaic. Therefore games feeling very stale since most of us have seen it all before.
Until people realize that advanced realism games can never be perfect they will never be satisfied. All the best most memorable games had some "flaws" whether it be visuals that go for a more artistic look, fun game glitches people liked to find out about so they can do it their selves, strange rumors about what is possible in games that may or may not be true, a deep mysterious lore and so on. The first Dark Souls was perfect in its imperfections. When From tried to understand the formula they created and tried to better "perfect" the formula the games got stale for that exact reason I said earlier. It became boring and formulaic. A lot of the fun got replaced with routine and so called polished crisp mechanics.
>tldr
Modern games shouldn't keep trying to be perfect. So many of the best games of all time have plenty of imperfections but they are fun to play because of these imperfections. This is why Dark Souls is my favorite game of all time.