Well, I'm thinking some time relatively recently, like maybe Late Pleistocene/Early Holocene. It would be really nice to be able to read that paper. I HATE academia.
A decrease in animals that feed on them could see a lot of butterflies. When I was on the Speculative Evolution forums I started a thread about future North American biomes given the presence and prevalence of a number of introduced species. The Emerald Ash Borer stands to radically alter woodland biomes, as many species of insects that feed a number of birds that in turn feed a number of reptiles and small mammals stand to either disappear or decrease drastically in distribution if there are no more ash trees.
So, what are some of the predators of the Tsetse?
EDIT: According to this
http://http://www.fao.org/docrep/009/p5444e/p5444e01.htm, they have very few actual predators. I looked up the ecological role of some of the three listed, and while all three include a variety of different species, the species that I have read about so far have very varied diets and I think would fair relatively well without the Tsetse. So from what I can tell, they don't play an essential part in the food web. They're just highly specialized to make everyone in Africa miserable. So their extinction would almost certainly result in the development of more advanced forms of agriculture, and probably the domestication of some animals, but also, probably the more successful radiation of African mammals during wetter periods of the Sahara.