Another way to look at it is that after Angola gets dropped, BA serves 9 countries generally associated with Africa, which amounts to 7 countries in the top 20 by population, plus MRU and SEZ. The largest countries not served are Ethiopia and DRC (probably not a good idea for BA for very different reasons) but with Tanzania (stopped in 2013) and Uganda (stopped in 2015) in 6th and 10th position. The elements that have changed since then are the 787 (in terms of cost effective aircraft), economic growth in Africa is reasonably good and the ME3 are not always that cheap now (cf Durban). I'd guess Zimbabwe will return if current trends continue past the election. Mombasa would be another prospect for LGW maybe, particularly if the risk of terrorism is reduced.