I spent 2008 in Tanzania, and I wasn't in a touristy area. There were still plenty of white people around. Missionaries, random people who'd moved there to live cheaply, and also tourists who wanted to get off the beaten path. If you went to one of the national parks or close to Mt Kilimanjaro, you saw tons of white people. Tanzania is full of beautiful places that are not full of tourists, though, and if you ever visit it is worth getting off the beaten path and finding the out-of-the-way areas. Lots of hospitable, kind, resourceful people.
In 2010 I was in Burkina Faso. Outside of the capital city you did not find hardly any white people. It's not the kind of place I'd visit as a tourist - there's just not much to see there. The interesting thing was that Burkina Faso had a reputation for being a safe place with less corruption than other African countries. I was never pressured for a bribe. It was said that a white woman could walk alone through the streets of the capital and be safe.
Unfortunately things have changed and there is now an active Islamic terrorist movement in many parts of the country. I still believe that the people there are for the most part very good and honest - I would trust a used car salesman in Burkina Faso 10 times more than one here in the US!
