To see the physical differences, all you would have to do is look at some of the photos/videos of actual African basenjis, from 1900s onward, and compare them to the standard basenjis which have been bred for generations to 'look' like what we feel a basenji must be (and not remotely African at this point). There is definitely a greater variety in the "true" Africans due to cross breeding with other breeds due to culture meshing: Curled to slightly curled tails, size variety, color variation, degrees of white, barkless/bark, etc….at least as far as physical characteristics go.
Beauty versus function is the key difference. That's pretty obvious. I'm unsure if the subtleties of personality vary much...more dependent on early socialization (Developmental/regulatory adjustment) than anything else. The only thing I've heard time and time about Africans are 1.) Loyalty 2.) Tendency to be more on the Alpha side... in comparison with standards which have been bred down for temperament.
The lines of Africans aren't heavily recorded- "unknown dog x", so it seems like it would be impossible to really keep track of what's what unless you created an environment where Africans were imported and put into an environment where they'd have to fend for themselves as well as regulate their own breeding patterns, for generations, and then have a record of what occurred...which would be classified as irresponsible ownership I'm sure.
Once you mix an African with a standard, essentially overriding nature...the African lineage is irrelevant unless you keep breeding into African lines...but then you lose select traits we find desirable (barkless, etc.) . In half Africans there is definite size/shape appearance difference....hence why you don't hear of many in the 'ring' ...but that gets more and more diluted down the generation line.
This information is what I've heard/read from those who have actually been doing the heavy work...just regurgitated.
Curious if there is anyone out there breeding only African imports with other African imports?