> Basically I need to figure out what imp's role is supposed to be in the face of importlib.

If it's not even clear for you, even if you eventually figure that out, having two import-related modules is likely to be confusing for users.
OTOH deprecating/removing imp would affect the somewhat popular imp.reload(), that has already been moved for Python 3, and will now be moved again (this also means that the -3 warnings on 2.7 will no longer be valid).