The problem with fictional nations (like Wakanda, Sokovia and Latveria) that they seemingly exist in a vacuum in a
'like reality unless noted' setting. They just don't feel integrated into the setting. Captain America works, because he is a super-soldier who fight Hydra in the sidelines of WWII. It does not effect history much, because having Cap doesn't lead to an early victory, as he has an equal force to counteract his presence. Then he is frozen, so MCU history more or less goes along the same broad-strokes as ours until Iron Man.
Sokovia works, because it can be imagined as of the Balkan countries only poorer than reality. Wakanda on the other hand is the most hi-tech country in MCU and no other nation noticed this. It needs enigeers, electricity, infrastructure to work. Nobody noticed for example that there is a lot of technological stuides in Wakandian Universities, seemingly no jobs in those fields, yet nobody seems to emigrate abroad? Okay, maybe nobody knows stuff likes this, because its the most isolationist country and it doesn't let anyone in. Why would world power - USA and China - multinational corporations go along with this. Would it be suspicious? The only country in the real world which is truly isolated is North Korea - it has only two neighbours - one of which is a powerful ally, and it has mines isolating it from the other one. And it has nuclear weapons and an oppressive regime. Wakanda has none of those. How can it be isolated.
And you can't just believe that whole population agreed to keep everything under the radar, because a country has both good and bad people, greedy ones, who would want to sell its secrets. And not to mention it has foreign embassies on its soil.
Do not get me wrong, I am not opposed to the concept of Wakanda. It's cool. If Black Panther was a one-off, a standalone film, I would be fully onboard with its afrofuturism. However I feel as part of the MCU it's a half-baked concept. Wakanda creates a vacuum. Why for example the SHIELD or its undercover Hydra factions haven't noticed its existance? Besides the Iron Man 2 cameo and the allusion in Age of Ultron, it was not wholly introduced until Civil War. They should have gave it some episodes in AoS or something.