`C-u g' used to show the raw article.  I changed that to `C-u C-u g',
  and made `C-u g' show the half-cooked article: After
  Content-Transfer-Encoding handling, but before article washing.

  Should we reverse the `C-u C-u g' and `C-u g' meanings?

We should be very reluctant to change the meaning of longstanding
bindings.   I want 'fully raw' most often.

Once you go beyond "100% raw" and "100% cooked", there are a larger
number of potential steps to be omitted.  So it probably makes sense to
use numeric prefixes.  An alternative interface would be to have some
keybinding following C-u g apply the processing steps one at a time.
I don't really recommend space (haven't thought enough) but how about it

  C-u g (fully raw) space (content-transfer) space (html/text select)
  space (wash) ....

and g when in incremental-cook mode got back to fully cooked and turned
space back to normal?