I will admit, I don't consider Mr. Bungle to be particularly "important" in terms of wide reaching influence.
Avant-garde is such a broad genre anyway, it's kind of hard to say how many of them even listened to Mr. Bungle, much less be influenced by them.
I'm not denying that there are bands influenced by Mr. Bungle, I'm sure there are, but I definitely wouldn't consider it "One of the most important albums in rock history."