This was driving me nuts. If you set touchpad delay it should only disable tap to click from the edges of the touchpad. This is reasonable and how it works on my wife's dell xps 15. However, on the surface book it only disables the *right* edge of the touchpad and *doesnt* disable the left, bottom, or top edge of the touchpad. Worse, it disables the right edge by roughly 4x what it should. So if you are tapping on the right 3/8 of the touchpad it won't tap to click. Basically, instead of disabling the left, bottom, and top edges it seems to be adding to and disabling more of the right edge and making it unusable for tap to click.
Edit: now that I observe how my hands brush the touchpad while typing I'm starting to think this might actually be intended functionality. While typing, my left hand barely hovers over the left side of the touchpad whereas my right hand hovers over the right 3/8 of the touchpad. I think the solution they came up with (to disable tap to click on the right 3/8 of the touchpad) starts to make sense, although you would think you should still be able to tap to click after some "delay".