If he were alive today, Marx would probably think that the working class is being exploited even more than it was in his time. He might think that globalization was creating even more surplus value that was being taken by the bourgeoisie and denied to the proletarians.
Globalization has, it can be argued, allowed people in factories all over the world to be creating more value. People in China, for example, create things like iPads that are sold all over the world, not just in one country or one region. In this way, these workers are creating much more value relative to what they are being paid. Marx would say that they are being exploited because they are not receiving all of that value.
Marx would also think that the oppression of the working class is becoming more widespread. People in the rich countries, he would say, are no longer simply oppressing their own working class. Instead, they are oppressing the working classes of many other countries as well. Marx would likely think that the spread of global capitalism is a very bad thing for workers.