Clearly you have no idea what Brazil is really about. There are less than an handful of countries, in this planet, that represent humanity - at its best and worse - as well as Brazil. In America, that's the US and Brazil. And, perhaps, in the whole world, they're the best examples at that.
Why am I saying this? Because Brazil and the US is what you have when you start a country anew in a new continent, settled by people from all Earth continents (bar Antarctica, of course), some looking for a new opportunity - a piece of the American dream -, others by force - a piece of the American nightmare.
Considering Brazil is, today, more relevant, economically speaking than the United Kingdom, considering Brazil, as I've mentioned, encompasses in its territory a cultural and human legacy few other countries do, and considering civilization, even if human, has never been fully detached from nature, a country with such natural legacy as Brazil clearly has a place in the Civ series.
I mean, the mere fact alone Brazil is a BRIC country, has a massive weight in a great part of the world (the Portuguese and Spanish speaking world), and has an unique, thriving culture (similar to the "staple" Portuguese culture, but different nonetheless), speaks alone.
I'm also saddened by a few Brazilians in here. I think it takes a foreign (as far as a Portuguese can be "foreign" in Brazil) to really understand how unique you are... and Civilization isn't completely made out of armies. Not to mention that, even on that, you're a force to be reckoned with - at least today, and relatively to its time, especially during the late stage of the Empire of Brazil and the United Kingdom of Portugal and Brazil.
Brazilian soldiers HAVE conquered Madrid in the past. Only they were called Portuguese back then (and most were European Portuguese either way, but the General spent most of his life in Brazil, and so did many officials and soldiers). Fact.
http://en.wikipedia.org/wiki/António_Luís_de_Sousa,_2nd_Marquis_of_Minas
P.S - I feel the Fatherland Volunteers will be the UU, because, as I've said, they were active during Pedro II reign. The Bandeirantes are, more than anything, a symbol of São Paulo, Portugal and the Portuguese Empire. So we'll see...