GNU chmod suggestion?

Would it make any sense to add support for flags called
something like 
"+R" and "+W" that act a little like
"+X"?  I frequently find myself 
needing to set make files writable by a group.  However,
sometimes some 
of the files are not meant to be writable even by the owner.
 Therefore, 
something like chmod -R g+W foo would make all files that
are already 
writable by the user or world writable by group.