Is he really, really overrated?
I guess he falls in the 'progressive rock' category but from 1969 to his last album there seems to be the same arppeggio, jangly guitar, and bass voice going 'YAAHHHH' on every album. The songs are heavily syncopated but seem to have the same syncopation at different tempos.
I feel like his music had very little creative work and was just one impulse driven manic piece after another with very little variation.
I'm a huge fan of Kronos Quartet. The pieces they play are dissonant, repetitive, sometimes enjoyably harmonic but each piece has a distinct beginning, middle and end.
I just don't understand what others get out of listening to Zappa.
Maybe it's like the Harry Potter book reading phenomena. You want to look cool so you buy the book but never read it. With Zappa you listen to the music once and then agree with whoever says, "Ya, it's great" because you don't want to look uncool.