I’m an absolute Apple hater so you’re plain wrong. 
But don’t you think there is a reason why Apple has not released an OSX tablet yet?
If you start to attach mice and keyboards to a tablet then you don’t have a tablet anymore, you have a notebook.
The finger argument was a simple test how it will look like if you want to edit 1/8" sized icons and buttons with a 2.5" sized mouse cursor. And the finger will be your mouse cursor if you start an antique DAW on a modern tablet. Again: If you use mouse and keyboard anyway for editing then then why buy a tablet?
You can buy windows tablets since the 90s (even cheap ones) and run normal desktop applications on them (even DAWs). Absolutely no problem. You don’t have to wait for the surface. But nobody ever wanted these devices because desktop applications on touch screens just don’t work and never did. The new surface may have longer battery life and more horse power but the usability of the desktop side is no different to the first tablets from 1995.
I’m not talking about Metro/RT. If we see DAW for the tiled area of windows then it will of course look and feel like.Cubasis or GarageBand. But I’ll doubt that Steinberg or any other manufacturer will ever write such a software. The latency for RT apps is much worse than even the first Android phones and MIDI is officially marked as “depreciated technology, supported in version: never” in MS’s developer area and there is not a single hint that this might change in the future.