I just read a pedagogy-themed essay on world systems, history, and Greece and Rome ("Placing Greco-Roman History in World Historical Context", E. A. Pollard, Classical World 102, 1, 53-68). I'm also slowly working my way through Ian Morris' Why the West Rules. It's not that often that you find ancient historians dabbling in the worlds outside their frontiers. Pollard and Morris, in their own ways, make the case that this should happen more often. But, significant obstacles stand in the way of the situating of ancient history into the wider world.
It's not easy to manage in the classroom. If you have limited resources - many departments are quite small - you have to be quite selective with what you teach. In this country (Canada), at least, most ancient (read Classical) history is taught as part of a Classics programme. Though this isn't always the case, Classicists tend to prefer to stick to hardcore Classics stuff: classical Athens, late republican and early imperial Rome, myth, Greek, and Latin. This makes a lot of sense: the languages are fundamental, and a significant chunk of the best-known literature comes from those historical periods. Those Classicists who might call themselves historians (not to mention those who aren't) are often called upon to teach courses outside of their specialist interests. Courses might be cross-listed with other relevant departments, such as history departments, but those other departments have little or no say in whether a particular course is taught in a given year.
Despite these challenges - and this might surprise the lay-person - Classics has moved on. It's now peopled not only by elite men from Athens and Rome, but slaves from across the Mediterranean (and beyond), women, both rich and poor, and, occasionally, barbarians, not to mention children (among many others). Moreover, the chronological scope too has broadened. It might stretch back to the Bronze Age and the Minoan and Mycenaean cultures (the reality rather than the Homeric version), include the competing empires of the Hellenistic world, and extend into the second, third, or even fourth centuries AD/CE, not to mention to the provinces (post-colonialism).
The range of evidence that's deployed is much more diverse now too. Reading Sallust, Tacitus, Herodotus, and Thucydides won't suffice - or at least reading them in the traditional ways (reconstructing political and military history). Latin military diplomas as evidence of family life in the provinces, the small finds (hair pins) for the presence of women (possibly) in male spaces, and provincial art (long belittled as inferior) as a reflection of the melding of the melding of centre and periphery among many other things have gone quite a long way towards broadening our understanding of the ancient world.
There is hope, and this much more inclusive understanding of the ancient Mediterranean has worked its way into the course offerings at universities around the Western World. In mine, for example, you can now take courses on the use of space in antiquity, Roman Egypt, the ancient family, and Persians, all with a chronological scope that runs from ancient Knossos (the Heroic Age) to medieval Constantinople (Arab conquest). But, there's good reason to think that we've pushed the boundaries in our department as far as they're likely to go, at least for some time.
How can we go about situating Classical history into wider world history when it's already taken this long to incorporate what we have? And, what sort of courses would serve these purposes? One on ancient empires, for example? Or the different ways that cultures have described the past? But how would you teach these? It's hard enough offering team-taught courses with members of the same department. How would you manage with faculty working across departments? There's also the issue of teaching load: who would get credit? Plus, if these courses were to have any measurable impact I imagine they would have to be taught as often as possible. Could this be managed year after year? Plus, although this might benefit Classics, how would it benefit other departments? Why would they agree to this?
Then there's the publication side. It's all well and good for established scholars like Ian Morris and Walter Scheidel to publish studies that explore comparative world history at large and wealthy universities like Stanford. But what about the rest of us (young and at small universities)? Can young scholars of the ancient world eager for jobs, promotion, or tenure really expect to write these sorts of things when it's entirely possible that those who determine their fates might be loathe to give credit for work that discusses certain materials cursorily (the comparative material)?
Fact is, there are still many Classicists who are vehemently opposed to anything non-traditional. Although I'm employed, I sometimes wonder if my choice to focus my research on parts of the ancient world far removed from the centre was worth the risk (Procopius, late antiquity, the Roman military, Balkans). On the other hand, if things do have to change (and I haven't even discussed if they ought to), someone has to start somewhere.