Herzog's other work has very similar themes, he hasn't matched the heights of Aguirre, but he's always interesting and mostly spot on. Also possesses a very confronting sense of humour which can have you in stitches at times.

Lessons of Darkness, The Enigma of Kasper Hauser and the downright hilarious Even Dwarfs Started of Small are the closest to Aguirre in quality in my eyes.