Duck of Minerva is currently running a symposium on "The end of IR theory?" special issue of European Journal of International Relations. In his article in that issue, "The Poverty of Grand Theory," Chris Brown (of LSE) calls for "critical problem-solving theory," i.e. theory which addresses real-world problems from the perspective of the powerless (or the underdog, to use the word in his abstract). I commented on Brown's DofM post (summarizing his article), and Nicholas Lees has a post on Brown's article here.
I think Brown is pretty much right that poststructuralist IR has not been sufficiently engaged with the real world and that both realist and liberal IR theory, while often quite engaged with the world, aren't concerned enough (or at all) with issues of global poverty and inequality. As Nicholas and I both point out, IR theorists could draw on resources in the literatures of international political economy, development, and applied ethics if they were to decide to make more concerted efforts to fill the gap(s) Brown identifies.
One might ask why it matters who is working on a subject (in this case, global inequality and related issues) as long as it is being addressed by someone. I would suggest it's important that more IR academics focus on these issues partly because they do connect to the discipline's main concerns, in addition to being highly important in their own right. The other side of the equation, as Nicholas suggests, is that there need to be 'addressees,' people who are willing to consider the scholarship that's produced and who are or might be in a position to try to act on whatever is actionable.
Writing this post has led me to take a quick look at a piece I have long been intending to read: Giovanni Arrighi and Lu Zhang, "Beyond the Washington Consensus: A New Bandung?" (It was published in an edited volume [link] a couple of years ago but I have it in a separate pdf.) From a glance, Arrighi and Zhang contend that the economic rise of China may create the conditions for the formation of a new Southern bloc, held together as much or more by economic interest as by political/ideological solidarity. China, India, Brazil, and South Africa, the key countries in this scenario, are consciously promoting intra-South economic cooperation and activity. The focus on the possibility of 'a new Bandung' draws attention to issues that used to have a more central place in IR, including questions about how the interests of states and governments connect (or don't) to those of struggling individuals. If one wants to make a start on the tall order of 'critical problem-solving' theory ('grand' or otherwise), perhaps bringing North-South relations back to the field's center stage would be a good first step.