This was originally posted over at Uservoice but lost in the conversion. Luckily I posted in Area as well... but alas you cannot convert a post to an Idea. So I'm updating here.
Cap Mapping is almost always Useless
In almost all instances where I've used the Cap function (either as a modifier or in the Border mode of Editable Poly) the results invariably require effort to fix.
Here is an example of an object that was split and the interior open borders were capped.

That is never the expected result!
Here is something far more appropriate:

Although the program cannot know automatically which edge to use for a UV-flow, it should be able to use the first edge in the border to create a flow. It should also be able to detect a planar surface and use planar mapping coordinates. This should be added to both the Cap Holes modifier and to the Cap function in Editable Poly.