The most instantly noticeable difference between Dario Argento's original Suspiria and Luca Guadagnino's 2018 cover version is the way each film chooses to decorate itself. Argento's film often seems intent on burning the viewers' retinas right out of their eyeballs. Many of its best effects are accomplished through abstractions: color, stained glass decor, the pulsing electronic Goblin score. Guadagnino's film, by contrast, is a grey, bleak affair, taking its cues from the dismal world of Fassbinder's 1970s Germany. Both films start with a woman seeking help in a driving rainstorm, but where Argento's opening orchestrates a world of peril and chaos, Guadagnino's opening is a portrait of misery and defeat. It wouldn't be right to claim, as some have, that Guadagnino's film is "artier" than Argento's, because Argento's films from the 1970s are all art objects to one degree or another, both as objects unto themselves and in their contents. Argento made films in which art is dangerous, in which art can be used as a weapon. It shares this theme with the new film. They just have different ideas about art.
Note: this is heavy on the spoilers.