I am not an expert, only a fellow test-taker. What I provide is simply my opinion.
Overall, your introduction is strong. I would hesitate to use too many GRE vocabulary because you need a mastery level understanding of said words and using too many would not allow for a proper flow, For example, in you opening sentence, the use of globalization, amalgam, and eclectic sounds awkward. Personally, I would try to spread these words throughout the essay and not write them back-to-back.
The second paragraph seems strong. There is a clear argument, with examples, however, the example of Chetan Bhagat's success does not directly connect to your concluding statement. You conclude the second paragraph with someone having bad grades. I believe it would be better to provide an example of how someone with bad grades will perform poorly in other fields of study.
The third paragraph seems to be contradicting your argument in the second paragraph. You clearly stated that if a person performs well in one field, it is likely the person would perform well in another field due to diligence and persistence. Yet, you argue in the third paragraph that these characteristics are not enough. Although each of the two body paragraphs work well on their own, they don't work well together in this essay because it seems like you're arguing with yourself. I hope my perspective is clear.
The conclusion is weak because you're introducing other factors and new examples to your argument. Rather, try to summarize what you have already written. In this case, I would personally have split that last paragraph and perhaps added a sentence or two to my conclusion.
Although I'm not an expert, I hope you my ideas will help in some way.