I do a lot of flights from London to various less obvious parts of Africa and also a lot of London - South America. That means most of the time I need to change at least once. If there's no direct flight my strong preference is to change somewhere in Europe into a long-haul direct to destination, ideally overnight.
So, Libreville is a change in Frankfurt onto the somewhat odd 737's with the mostly biz configuration; Lome probably best via Accra, Freetown I would go direct, and so on. South America tends to involve Madrid.
But, because I'm not paying, it will be any direct flight unless an easy alternative is much cheaper. All this in biz class.