I think I have never read the article better than this on the topic; concise and focused. It shows the clarity of Mr. Usman Hayat thoughts on the subject. However, without taking the credit I want to add that the barrier to economic justice is the elite capture (of financial and political institutions) and not the principles of Islamic finance. Generally, economics and economic justice is discussed in isolation to politics and society, which couldn't be. The blame to both type of institutions looks wrong, since conventional financial institutions and markets are playing on their own ground, having enabling economic and financial architecture. Let Islamic finance work in it's own enabling environment, and then we should held them responsible economic justice is not provided. Still many issues that trigger the financial crisis are absent in Islamic finance.
Regards