That seems like a lot of assumptions: Mali is an islamic country therefore it has dhows, Mali is in west Africa therefore they have access to the excellent Yoruba people's swords. Also the Dhow, though reliable is not quite as good as the Caravel. The dhow was held together by glue or lashes while the Caravel was held together by nails. The dhow could still likely sail to South America, as Thor Heyerdal did so on a reed boat across th pacific.
I don't think the Malians are the right africans to sail and colonize the Americas. Their Empire was a huge land-power, and the government had a hard enough time ruling over it for them to attempt to properly settle and colonize the Americas.
The POD has to be with Muslim rule over Iberia, and then perhaps the Morrocans or Cordobans could settle the Americas.
On the access of the Malians to the Dhow, they did have
access to the dhow via their contacts with North Africans, and they built them on the coast of Senegal.
On the aspect of my argument for West African metallurgy, I was talking about West Africa as a whole, which is similar to talking about Europe as a whole in terms of difference between cultures, and why could the Malians not get access to Yoruba swordmaking once, or for that matter before, they had a transatlantic capable navy?
Why does the POD have to be Muslim rule over Iberia? Why could the Malians not get to the Americas without the Iberians, which I have shown to be quite plausible, or for that matter, why could the Maghribis not get to America without complete control of Iberia, especially as Iberia is much farther from the Americas than Iberia and that the Central Atlantic is calmer than the North Atlantic? Why does it matter much if a ship is held together with lashings or with iron nails, and when clearly the Islamic world knew of both, why did they choose the former?
BTW, to me it really does not matter the specifics of the tactics or the weapons used by the Europeans, because in this timeline they never gain a foothold in the Americas in the first place, making the matter moot. Mali would have a couple centuries to gain a presence in most of the Americas, so what could tiny Portugal, the Netherlands or slightly larger France, Spain or Britain do about it? I think we should move forward with how the Malians would relate to the peoples of Amazonia and what their routes of exploration would be once they gained a foothold there. Also, how would Malian society be changed by new crops, ideas and goods from the Americas?
I, personally, see (as I said before) a much less exploitative treatment of all of the Amerind societies, including the ones not yet even settled, based on trade and maybe tributary relations, with the Malians as the dominant player of course, and mutual alliance for the Mississippians (which had yet to collapse by that time and could be revitalized by trade and influence with and from Mali), the Andes and the more developed societies of Amazonia. Mali would overshadow Europe with its connections to the Americas and prosper from trade with the former, while maintaining its position via a huge navy. Due to Mali's position of power West Africa, their would be no transatlantic slave genocide, for even if slavery occured (though it might actually quite quickly disappear;
see here for a possible reason), it would not be the same dehumanizing slavery of the Europeans that happened in actual history.
Eventually, the Malisphere would establish contact with China, India and Southeast Asia, and establish more or less fair and respectful relationships with each, though of course their would be wars, though probably mostly naval (with the Chinese and the Southeast Asians, probably). The Mandinkan language of Mali would a major world language and a Classical language.