Yeah quite a few hills in de Ronde are harder than Amstel. The only thing that makes Cauberg interesting is it's location and the steep pinch being right at the start. And in Amstel it's generally the accumulation of hills and the Eyserbosweg/Keutenberg/Kruisberg/Fromberg is proper Ardennes terrain.
There was a Tour stage finishing just after the Cauberg once with not much else and it was a bunch sprint.
There probably have been other finishes after the Cauberg, but in 2006 Kessler won solo and Rogers I think genuinely outsprinted the sprinters left for 2nd.