I think for the Millennium trilogy (as those movies and their original books are called), one needs to be a bit acquainted with the wheelings and dealings of the already deceased author of the books who were the base for these movies. There is a strong background of researching and dragging old Nazi connections in Sweden into the light of the public (I guess, also government corruption in general too). Such which, on average, are way more involved in sick crimes, especially such of sexual nature and especially against children, than they always like to admit officially.

So, these movies are best seen through the lens of what life is like in Sweden and what things are issues in Sweden. Not just through the lens of "another good or bad movie", what Hollywood tried to do with their compulsive remake (that is rather unrelated to something from the reality).

Ah, yeah, by the way, the Millennium saga is even unfinished in its book form until today because the author died in between. There supposedly are notes and manuscrips of what a couple of further books would have been like, but they are incomplete.
So... who knows what he had once planned ahead. Mabye he had envisioned some more content for the character Lisbeth Salander. And this all would have been a series lasting for much longer.