I'm new to the game and I don't know about FFXIV specifically, but the brazilian player base in MMOs is quite large. I don't think a brazilian data center should be created, but a south american one would be a big help and I believe the player base is large enough to justify it. I don't mind playing with people from other countries (in fact, I like it a lot), but the high latency would make me consider a lot moving to a local server.

Truth is there are no words even about an EU server, so I we shouldn't expect a SA server anytime soon ):