Without a doubt I would consider Ngeny over El G a "higher profile" upset as Hicham is the greatest ever, but is it "bigger?" By that I mean more of a shock.
Ngeny is the 2nd fastest miler ever, 6th fastest 1500m runner ever (3rd at the time), and the world record holder in the 1000. If he never got gold, he would surely be the greatest (distance runner anyway) to never do it--likely over Sihine and Tergat.
Wightman is a 3:29 guy and even a common medal pick in 2021. Plus Jakob is only 21 and hasn't been as dominant as El G was by any means. But Wightman only finished 10th in Tokyo. Ngeny was 2nd the year before 2000. And Jake raced Jakob once this year and finished 4 seconds behind him.
It seems strange to suggest given how big of a deal Sydney was, but I think there's an argument to be made.