Like many, Dembrowski and Depp had fond memories of the ABC telepic and series The Night Stalker, and they got Disney's Rich Ross and Sean Bailey sparked on a pitch for Depp to potentially play tabloid reporter Carl Kolchak.
Johnny Depp needs to work with Gilliam again; his best performances (i.e. Ed Wood, Raoul Duke, Edward Scissorhands, etc.) were under the direction of either Tim Burton or Terry Gilliam. As Burton hasn't made even a remotely decent movie (besides Big Fish and Sweeney Todd) since the nineties, and his work is becoming worse and worse, that means he's out of the question.
Depp himself is also going downhill (thanks to the dreadful POTC franchise which proved that Depp needs a director who can restrain him, unlike Gore Verbinski), and it's a shame seeing as he is a great talent, especially when it comes to using his facial expressions, gestures and body language to act-however, his impression of Keith Richards in POTC not only went too far, but wasn't a very good idea in the first place.