Wakanda is definitely not something we need in this game, in my opinion anyway. Keeping in mind the target demographic of Final Fantasy in general, I do not believe that those who were so strongly taken in by the aesthetics of Heavensward and Shadowbringers specifically would be able to put up with an expansion where those elements are completely lacking in favor of a dominant "tribal" theme or an overwhelming technological presence at the very start.
This isn't to say that smaller tribes shouldn't be present in future expansions, far from it in fact. Whenever we do go to the New World they should have some type of presence, but I do not think more than a zone should be dedicated to that. Also please do keep in mind that "Africa" is not just tribes-ancient Egypt has plenty to draw from that could fit a high fantasy theme without being too on the nose about where they drew inspiration from.
As for Central America, I do believe that served as some inspiration for Ronka, so I do not expect that to resurface again so soon. An alternative way to draw from that region would instead be cities such as Mexico City, with its Spanish-style architecture, cathedrals, churches, fortresses, and all. Central America is a lot more than Aztec ruins, and I do not believe that people with links to the region would like if the only representation of it was the same temples copy-pasted across so many different games.
FFXIV's method of trying to line up real world-inspired locations with their corresponding geographic location in game is a trend that is not sustainable in the long term if followed to the letter. There is no reason why Meracydia and the New World cannot have their own various kingdoms and empires in addition to smaller-scale tribes, with castles on one end of the continent and tribal villages on the other. They can compliment each other if done well, and still be palatable to the Final Fantasy audience.
Speaking specifically for myself-you would not be able to sell me a "Wakanda"/colonialism/tribal themed game even with the Final Fantasy title attached to it if I had not already sunk 8 years of my life into FFXIV since the day ARR launched, and even I don't know if I would stick around for something so lacking in traditional fantasy elements. I even stomached FFXV and FXIII despite their aesthetics being wildly different from most things I'm used to because they still had their own magic and lore underlying their otherwise modern settings.
Contrast this with FFXIV: we have killed both of the two major deities of the world along with nearly every other god summoned by the beast tribes. The last of the mothercrystal's energy was consumed by Zenos to become Shinryu again to fight us at the edge of space. Zodiark's fathercrystal was seen briefly during his fight whenever he spun the stage, but is otherwise seemingly gone or of no longer any importance so far. With Garlemald in disarray, I can only hope that rather than turning their conquered territories into a series of republics that at least a few revert to monarchy, but given previous trends there's a decent chance they might form something akin to the United States of Ilsabard.
The world is left godless, bereft of many of its original (known) kingdoms in favour of republics, with almost all of its major mysteries having since been uncovered or resolved. At this point we need a major return to magic, to true high fantasy in order to bring things back on track. I do not believe that sending us into a jungle or to mingle in some kind of colonial-based conflict is the correct way to proceed from here. You'd lose me if I wasn't so attached, you'd lose a decent amount of people who that sort of thing just doesn't click with, and it would fail to get the attention of the Final Fantasy core base.