I think other devs should focus less on trying to imitate FS and more time developing their own style and substance. If there's no founding ethos to your work, the main content will never be supported to the same level as FS titles.
It's also a shame, because not many other devs have this level of artistry in their work. I haven't been able to play a Ubisoft game since my first run through of DS1, as an example. Those Uni games just feel so hollow and soulless in comparison. There's no joy in the experience.
Firaxis is generally a good comparison in my mind. When I play the Civ series, I can feel the passion put into the games.
Probably also why I prefer indie titles over most AAA games too.