That's the problem though; you're never going to get a situation where the fate of the entire African continent hinges on any one or even one series of related events that could meaningfully result in a single war, because the "proper" ownership of such a vast swath of territory is never going to be disputable. Sure, you have some strategic points that smaller wars might get fought over, assuming it isen't just brought up to international arbitration (The usual procedure). Ivory is also not priceless, especially by the time of mass industralization and African colonization roles around, nor was MOBALIZING all that labor even somewhat viable. You're thinking far too much in terms of pure, "gamey" potential rather than practical terms.