Any t**t can throw some deep ominous chords together. It needs to be a real orchestral composer who has a broad command of styles if it's going to convey anything of the haunting majesty of Goldsmith. Of contemporary composers I rate James Newton Howard as he's come up with some scores that have had some emotional impact above all the thudding driving stuff that's been the mainstay of soundtracks the last decade or so.
I'm in two minds about the merits of Hans Zimmer. Perhaps post Pirates of Caribbean a lot of his scores have been about bangs and thuds and driving rhythms than can seem too generic, on the other hand Gladiator is a masterful score. Man of Steel, Intersteller etc all feel a bit vague and pompously grandiose without actually building on anything except volume.
What Streitenfeld did for Prometheus was, certainly in the more modern generic style but still had it's merits and stand out moments, Space Jockey, Collision, Invitation, amongst others.
I don't think there's anyone really of the quality of Goldsmith, whether it's stuff that went unused or not, everything he created for A L I E N matched the visuals, the sweeping yet sombre stuff caught the tone of Cobbs design, and the discordant haunting motifs matched Giger's desolate world and derelict. As did a lot of the unused material that symbolised the alien itself. He was not a snob about using synthsisers or any other more peculiar instruments that might lend his scores a unique feel, but if a contemporary score has any hope of capturing the essence of what made A L I E N such a nerve heightening score it needs to be built around a full orchestra first and foremost IMHO.