Is it specifically ,Net 3 or could it also be 3.5, 3.51, or higher?
The *tool* only requires .NET2, but inasmuch as Microsoft only supports .NET3.5.1 .... :-)
The issue being, there's no .NET2/NET3 on a WS2012/WS2012R2 system, and I doubt installing .NET351 is justifiable just for this task.
What if on the remote server, we change the server name (and eventually the port number) from "update source and proxy server" instead of using the wsuschangeuss utility?
That's always an option. It's the original methdology.
The intent of the tool was to eliminate the need to do this on several, or dozens, or hundreds of downstream servers. It was this need of an actual customer that resulted in the creation of the tool.