It's not the pen, as such, but the tablet which needs to be Wacom based. That is the part which contains the patented technology and, as far as I know, only Wacom have come up with a system that achieves their level of precision and they protect their patents. In this case, Asus do use a Wacom system, but the Surface Pro does not.
However, I see no reason why it shouldn't do as you suggest. The main issue I would predict is not so much the accuracy within the screen of itself, but rather the affect that the screen size has. In other words, you will need to be 100% more accurate with that than with a Cintiq21.
Ultimately, though, zooming in to objects will get around that, to a degree, but it is more difficult to use smoothly. Having said all that, The Cintiq itself has issues, especially in terms of calibration and edge accuracy. Also their Window 8 drivers are very, very buggy, so it's not clear cut.
You may well find that the extra touch functions are more useful than the disadvantages, price being one of them!
2013 : My new year's resolution -
To not post anything negative. If I don't have positive advice or support, even if I'm wrong. I won't say anything at all!