Arpeggios or respective broken chords can be a great tool for accompaniment patterns or sources for melodic gestures. On accompanying figures they help to establish a sense of harmony but also keep a steady rhythm going. On melodies they help to “bridge” large melodic gaps in a plausible way.
However, simple triad arpeggios very quickly sound overly simple and stylistically more in the field of Mozart than modern film music. One very simple trick that might help is to not have a triad arpeggio going on (c e g e c e g e c) but instead use the ninth of a chord for the pattern (c d g d c d g d / d e g e d e g e). With this little alteration, your arpeggios will create a little more hamonic interest. Other possible options would be incorporating the major 7th or minor 7th into the arpeggio. In fact, any “non triadic” note will help to give the arpeggio a more interesting quality.