Class struggle issues do indeed apply to the system known as "globalization," which is essentially warmed-over colonialism based on an assumption of near-zero transport costs. The WTO is just the British East India Company in modern costume.
I've found that some of the writers of the "Braudel School" offer a lot of insight into these issues. While not Marxist as such, they do make use of some of his better ideas, and go on to analyze political and economic relationships between "core" and "periphery" on an international level. They also examine the issues in a context of deep historical time, over the 500 year period dominated by our present system of nation states that co-evolved with capitalism as we know it.
I'd recommend
Immanuel Wallerstein, whose books include
World-Systems Analysis and
Geopolitics and Geoculture, and
Giovanni Arrighi, whose very comprehensive work
The Long Twentieth Century actually goes back and starts with the 14th century in setting the evolutionary context for the 20th.
Fourteenth-century Florence was where capitalism (aka banking) in its modern form got started. Arrighi shows, for example, how a labor revolt by the wool-workers (
ciompi) was an almost immediate consequence of the new system.
These writers bring class struggle into a new perspective, taking more of a systemic view of concentration of wealth and power as it occurs in capitalist nation-states, and less on individuals' identifying with "class" as a group that they belong to. Either way, it comes to exploiter vs. exploited, and how that dynamic occurs.
If you're doing any research on economic inequality, and how it gets institutionalized globally, these guys are a must-read.
Happy hunting!