Not sure this is the right forum for this, but on the Cython bug tracker, the problem of managing to use the C API for importing modules came up: https://github.com/cython/cython/issues/2854#issuecomment-466487200
If Stefan Behnel, who is one of the most experimented persons in the world with CPython's C API, has trouble getting it working, then probably it deserves improving. ;-)
(I also realize that the C API is more or less married to the dubious semantics of the standard "__import__" function, which is itself difficult to change, so perhaps a better C API isn't very easy)
CC'ing Stefan in case he isn't subscribed and wants to chime in.