Interestingly the data loss argument wasn't aimed at you, but at someone arguing they just needed their laptop with a big HD and nothing else.
There's many options for providing yourself access to the desktop at home from a mobile location, at which point you can access those obscure files.
It does seem that the tablet isn't a great product vehicle at the moment for a Tb portable desktop.
Whilst I love the 10" form factor and the light weight of the Surface there are times where I need something obscure and rarely accessed, and don't have my drive with me. This is frustrating beyond description.
Also not sure about the data loss argument, as I back up regularly.