Looking at your requests on this you should realize that repotags are what you are really asking for the minimum level, which is what epel nuked to ashes. So the discussion should probably move away from this list to the epel list. And since it's a dead topic there as well you will not really get very far.
I know EPEL acknowledged that the whole repo-conflicts thing is an issue that needed to be addressed... as has been rehashed many times, they just didn't like repotags.
However, perhaps adding something into RPM itself could go a long way to addressing this in a more integrated manner?
https://www.redhat.com/archives/fedora-devel-list/2007-July/msg01537.html
That thread might be a good place to request that something like this be added.
Not sure how high of a priority everyone would consider it.
Ray