So here's the deal. I'll talk about what I know. In Latina America we have a clear prominence of Spanish speaking countries. From Mexico to Argentina Spanish is a common place, to a certain extent. But some terms and the utilization of the language differs quite a lot. In Colombia, for example, they speak a lot more "formally" than in Perú.
A Basic SEO example can be pulled by looking for search terms in different countries. In this case I'll use google Labs' Google trends.
We'll compare Mexico and Argentina on 3 terms "PC" (blue), "Computadora" (red) and "Ordenador" (orange):
As it can easily be deducted "PC" is a far more popular term than "Computadora" in Argentina, while in Mexico "PC" is still number 1, but "Computadora" is very popular as well. "Ordenador", only appears (slightly) in Mexico. These are slight but important differences.
Thus SEO for countries speaking the same countries should not be the same. Although, in LA "neutral spanish" is used (is a use of spanish that is from everywhere and nowhere at the same time) some words should be localized in order to make it more appealing both to readers and to search engine crawlers.
If language use differs in not so distant countries picture what the cultural differences are from north to south, east to west, continent to continent.
Now we're getting to the interesting part. How can coroporate branding and identity be broad enough to appeal to every culture? Is this possible without being "bland" or "shallow"? It is possible. But it takes luck, inspiration or genius. Either that or your "corporate image" must be flexible enough to allow some localized content.
So you have a two way road. If you have a strong "trans-cultural" image you should stick to it (apple comes to mind, and even they have changed it over time -evolution- and have a broad spectrum of possible look and feels to choose from, with a "scent" to apple). The other road is to have a more flexible approach, allowing certain regionalization to appeal to the broader public.
I'd rather have a strong corporate identity, but if I ain't got that, I'd settle with option number two.