Casting to a flat 1-D array of bytes is reasonable (it's essentially saying 'look, just give me the raw data, it's on my own head if I stuff up the formatting').

However, requiring an explicit two-step process for any other casting (i.e. take a 1-D view, then a shaped view of that flat 1-D view) also sounds reasonable.

So I agree with Victor that 1-D bytes -> any shape/format and any shape/format -> 1-D bytes should be allowed, but I think we should hold off on allowing arbitrary transformations in a single step.