The movie had some fun action scenes and Mackie was believable. But the writing wasn't great and they completely wasted Giancarlo. The overall plot was predictable, you could basically guess major moments from the previews. Still, even if they did everything right it would be difficult to make this a truly great movie. This passing of the mantle strategy is tricky. And, I think Marvel struggles to answer 2 of the most core questions for the character: "who is Sam Wilson?" and "why is he now Captain America?". I think they could have come up with some heartfelt answers here but so far what the MCU has mustered is Steve Rogers wanted to go back in time to bang Peggy and Bucky basically saying Sam is captain America because 'you're you, bro'.
I guess I must have liked this movie more because I didn't watch any of the trailers or knew anything about the movie other than this is the one where Sam Wilson is now Captain America.
