And which one would that be?
There's the M theme in Voluntary Retirement and Mother, the urban theme in Shanghai Drive and Adrenaline, the exotic motif in Komodo Dragon and Enjoying Death, Silva's ostinato in Someone Usually Dies and Deep Water, a signature bitonal chord progression (try and sustain and Em chord in your left hand, and play another Em chord on your right, followed by an F# chord) heard in Someone Usually Dies, Kill Them First, Breadcrumbs, and The Moors, Severine's theme heard in Severine; Modigliani and Komodo Dragon, plus the Adele theme.
Whether or not you find them memorable or hummable enough is up to you, but I'm fine with 'em.
Komodo Dragon sounds exactly like something Arnold would do.
The Adele bit is a bit reminiscent of Arnold, but the second half with the bamboo flute (probably a Dizi) and Gamelan ensemble is pure Newman. Sounds nothing like Persian K-Mart music though, whatever the hall that sounds like.
Overstatement pushes drama into melodrama - something Arnold often did with his Bond scores.
Maybe, for some folks, melodrama isn't a dirty word. (That's not saying I'm particularly fond of Arnold's brand of melodrama, mind you. I can't stand "Paris and Bond.")
Melodrama was very hard to do right without coming off as phoney. You've got masters like Vincente Minnelli, and then you got Paul Haggis.
For a movie series so closely identified with its musical themes, not writing any sort of obvious thematic identity is simply not acceptable.
Newman's score does have a thematic identity.
But not an obvious one.
Pearls before swine.