Baroka symbolizes the beauty and stability of African cultures by being the clever leader of their town; he manages it in such a way that they still practice important traditions but also shows the beauty of the culture in the way that he makes changes to better serve and protect the people in their community.
Baroka serves as the foil to Lakunle. Lakunle is more interested in not keeping to traditions which is why he refuses to pay the bride price for Sidi, who he claims to love. Baroka, on the other hand, tricks his wife and convinces Sidi to marry him by also tricking her; at the same time, he pleases her by offering to put her face on the stamp. While Lakunle is bragging about how the village will modernize quickly, Baroka is respecting the culture and its stability. He's moving it forward in a way that isn't disruptive or disrespectful.
In the end, Sidi's choice—to marry Baroka—shows how he is the positive symbol of the beauty and stability of African culture. She says that he'll always be more fun even though he's older and that Lakunle —the modern man—will get older and lose his sparkle.