I started diving into SQL as the problem. Recently windows updates for my server suggested that I upgrade SQL server 2014 to Service Pack 2 as an optional update. It seems I have a SQL 2014 version from July 2015 (it was quite difficult to figure this out BTW). I plan to install the update today at the end of the day, but something I found recently was an ArcMap patch that deals with SQL: ArcGIS 10.5.1 (Desktop, Engine, Server) SQL Server Permissions Patch. I tried installing that before uninstalling, cleaning up leftovers and running a registry sweep for anything ArcGIS.
Although the SQL patch deals more with server permissions and not really the issues being brought up in the other thread, it seemed to speed things up! Specifically, it lets loose the chokehold on bringing up properties (the core issue that started the thread). Georeferencing goes much smoother...
In regard to the other thread, it seems you were going somewhere with having a fresh install. I shot it down in frustration, my bad. Being that I have a concurrent license there are certain things that have to be done to check out a license. I like to upgrade when I can because I don't have to play with those settings again.
My hope is that ESRI found the real cause and delivered it in this SQL patch. If not, I will try the fresh install.