Wrapping is also bug-prone. htod could fail to translate a header file perfectly, and it won't work good with macros. E.g.: http://stackoverflow.com/questions/5204460/problems-converting-a-c-header-to-d . You could accidentally put the wrong calling convention (or rather, htod will), and this will give you runtime errors which are hard to figure out. So having some unittested wrappers in Phobos would be good.
It would also be a good time to get rid of the win32 wrappers in Phobos and replace them with the more mature WindowsApi: http://www.dsource.org/projects/bindings/wiki/WindowsApi