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.