In the current Economist there is an excellent (and long) article on what the development community has tried to do for Africa, the lessons learnt, and what is needed going forward. The article is a good synthesis of much of the recent academic research, but is also full of very telling concrete examples and tidbits. One of their stronger arguments is that size does matter in development, and that grand macro-solutions can often fail to address the nagging micro-foundations and constraints. They also give focus to the need for improved monitoring and the acceptance of slow wins.
Specifically regarding the World Bank and private sector development they say:
“The Bank's thinking has now moved on [from large capital projects]. It worries less about filling a financial gap and more about improving a country's ‘investment climate’—the policies, regulations and institutions that can be kind or inhospitable to the spirit of capitalism. A new UN report reckons that Africans hold 40% of their financial portfolios overseas. Were Africa able to attract this money back, its private capital stock would increase by about two-thirds.”