It would be nice when 'quilt' (http://savannah.nongnu.org/projects/quilt) is supported for managing the patchsets. When having packages with much patches, it is often difficulty to rediff them as multiple patches might affect one source file and the usual 'gendiff' will fail then.
'quilt' eases rediffing and generation of new patches very much (e.g. see its manpage).
To use 'quilt' a
| %patch1 -p 1 -b .foo
has to be translated to
| quilt import -p 1 %PATCH1 && quilt push
The '-b ...' is to be ignored. The conventional 'patch' method must stay but there should be a way to switch to 'quilt'.