CONCACAF has 41 countries to CAF's 56 so I guess it is fairly even.
CONCACAF's Qualifying structure does not need fixing, it works fine for what it needs to accomplish and it isn't very different than the Asian one. It will probably change if CONCACAF ever gets 4 bids (then it would be almost exactly like the Asian one). I mean you could go to 2 groups of 4 for the final round but that would be less competitive than the Hex.
Africa certainly needs a change, you have to win a group just to advance to a playoff to advance,. It is remarkable that that format is allowed to be used.
But it's not really impressive, at least to me, for Africa to have 3 different countries reach the Top 16. I mean that's 3 out of 56 in comparison to 2 out of 41 for CONCACAF and 2 out of 47 for Asia, statistically it's fairly consistent with the others. If they went to a WCQ format that allowed for more of the elite nations to qualify consistently and improve their performances, then maybe I'd be more impressed. There is always one good African team, it was Nigeria, now it's Ghana, the only difference between them and CONCACAF is that Africa is very cyclical.