The MCU has utilised the twist convention like the very best of them. Subverting expectations, when used wisely, is a great way too beef out stories and give the fans some memorable food for thought once the fights and explosions have ran their course.
Confounding audiences often involves taking their existing knowledge of the stories/comics, and implementing a glaring change to the classic formula. Unbeknownst movie-goers are often refreshed. Die-hard enthusiasts are sometimes very upset, but more often than not, the gamble was worth taking.
It also goes without saying that some twists work better than others. A side-note warning to Marvel Studios may be for them to not rely on twists too heavily in the future, as it's a narrative tool easily prone to stagnation if abused to the point of predictability.
They might be thinking the same thing, so who knows where the movies will go 2020 onward. In the meantime, let's take a look at worst and the best of the MCU's jaw-to-floor moments. To add just one more unexpected twist, spoilers lie ahead.