Server Manager from the Command Line

C:\servermanagercmd -remove dns adds-domain-controller gpmc

To be fair, that was quicker than stepping through the "Remove roles" Server Manager GUI, even with needing to spend a few minutes on the servermanagercmd.exe Help screens since the syntax was brand-new to me.

But "servermanagercmd.exe" is still a long-a** name for an executable if you can't use tab-complete to type it, and I doubt that it's going to see much in the way of an adoption rate.