I'd say maybe a 3.5. Your position is not clear, and there doesn't seem to be a unifying thread throughout the essay. Your opening sentences in both the first and second paragraph seem to imply you mostly agree that major cities are a good indicator (which is also what you mentioned in your outline notes), but then the rest of the essay shifts towards "actually, major cities only give you part of the story and you really can't tell anything about a society without studying the smaller cities."
The second paragraph goes onto a tangent, arguing the original essence of a culture is lost when traditions mix. I cannot see how that adds to the argument.
The topic sentence of paragraph 3 makes me wonder where you're going with this:"religion has been shifting greatly in the last few years" does nothing to advance your argument. Sentences 2, 3 and 4 of that paragraph are generic statements and again I can't follow how they help your argument. Only towards the end of that paragraph do you get to your idea which basically is "the influence of religion on a society's values is much stronger in smaller towns"; the missing piece here would be "...and therefore using large cities as a proxy for society as a whole would be inaccurate, as it would fail to take into consideration nuances only visible in small towns."
Paragraph 4 could be strengthened by adding some more context. For example, define why you believe political views are part of "the most important characteristics in society" -- and, again, make a statement to link it back to the original prompt.
Finally, your concluding paragraph again makes me wonder where you stand on the issue. In your opening you implied you were mostly in agreement with the essay prompt; here you conclude by saying that you cannot truly understand a society without considering the small cities.
And a final note: you use a single example throughout (Colombia) - that's not necessarily bad, but if you're going to build your entire essay around a particular example you need to make a much better case as to why you think that example is sufficiently representative (and why you can use it to generalize and support the essay prompt).
