EDIT - money where one's mouth is time. Here's my take: There's some great stuff and some slightly less convincing stuff in the original 'Material' concept pitch but the problem is that the devil lies firmly in the details and it's already getting Cargo Cult-ed to hell and back - even in Google's own core products.
However - I've generally found the quality of the critiques to be far below the quality of the topic being critiqued and I'm quite comfortable calling people out on lazy reactions if they haven't bothered to convince me that they've given the subject the attention it deserves.
EDIT2 - Another thought has congealed after reading some more comments. The cargo cult is partly the fault of the original pitch. You can't propose something that is ostensibly as based on abstract principals as 'Material Design' is and only give a single implementation as the example without inviting people to fail to see through the surface details. Show us 'Material Design' with a completely different look and feel and then we might find it easier to grok the underlying principles and not get hung up on the specific choices made for this particular implementation.
Or to put it another way - how would Material Design look if you wanted to distance yourself from the new Google branding as much as possible? What would remain constant?