Rebuilding a package is the easy part... removing/adding a package to the download server is slightly more complicated, but in the EPP p2 repository at
http://download.eclipse.org/technology/packages/mars it's not that trivial to remove the p2 metadata for just one package. But it is doable with a p2.remove.iu and that's what I did now in the M7 packages metadata: I removed all IUs that belong to this package. It shouldn't be possible to update/install the DSL M7 package any more.
(In the past I ignored this part of the story, i.e. the removal of a package from the p2 repository that received a -1 by its package maintainer, because nearly no one updated the milestones with p2. In those milestone cases it was enough to remove the package from the download page and leave the EPP p2 repository as it was. But now, with the Oomph installer using this metadata, it is more important to keep this all consistent. To be honest, I don't know if the Oomph product catalogue needs to be rebuild now (?). The positive side effect of this: It's good to get some experience with this in M7, just in case there's something similar happens later in the release.)