Its possible that Wakanda did briefly appear when Captain America jumped off a pick-up truck marked IFID into a government-looking building; assuming this indeed stands for Institute for Infectious Diseases, and looking at the logo and camouflage colour scheme of the truck in question, its a safe assumption that this organisation is based in Africa. Even so, considering how important the fictitious African nation is rumoured to be in the hunt for Bucky, a brief glimpse of a building hardly qualifies as a real look at this country. In the comics, the nation is depicted as a rich, scientifically-advanced kingdom. Seeing Wakanda is thus a anticipated event - will this hold true for the MCU, or are Marvel going to scale it back considerably, making it a generic African country. On a similar note, despite seeing a few awesome shots of Black Panther in action, there's no sign of TChalla, his royal alter-ego. Just another reason to think that Marvel is deliberately withholding this diverse and unique location from us for now.