I get that Mali has architecture that would be recognizable, perhaps more so than other subsaharan African countries. I actually agree that it would be nice to see Africa (beyond morocco) at world showcase, but I guess the thing is that what most people associate with Africa (vast wild spaces, wildlife) isn't easy to replicate in an instantly recognizable way like a Japanese temple. I do think that Mali's current situation makes it a poor candidate, though, or at the very least it could end up being the butt of a lot of jokes if it were added.
Africa is so well-represented at AK and AK lodge that I don't feel so bad about its absence at Epcot.
I think Oceania and Polynesia are underrepresented at wdw though.