Now that we are heading towards what could be the end of the current form of the MCU, what with Infinity War on the horizon, is it time for the Avengers to learn that Coulson, a former ally of theirs, is still alive?
I say yes. Now, I am aware of the numerous difficulties of connecting the Marvel shows to the Marvel movies. And I am also aware that the actor playing Coulson said that he thinks the Avengers have moved on from his death. However, Coulson was a big part of Phase One of the MCU, and was used by Nick Fury to be the reason for the Avengers to unite against Loki (speaking of which, he also has to face off against Loki and get some closure there). It just seems odd to me that with so many years passing, and how public his version of SHIELD has been getting, that there still is this big secret.
So, a cameo of him in the final movie should suffice.