It's been a while since this post was listed, and I believe this is a topic that SW Soft should act upon immediately. Domain users should only have the rights to install packages that are assigned to them, just as resellers can only view and install packages assigned to them, and default such as all and nothing should be in place as well.

Currently, what I'm planning is an area to add or remove the Site Applications button completely, when installation of a package is requested by a reseller only. If any one else has any better ideas, I'd be happy to hear them.