What is it with Phil Coulson? Is he dead, alive, human or android? Who knows? But since Agents of S.H.I.E.L.D's mysterious scene regarding what really happened after his apparent "death" at the hands of Loki in the Avengers he could be any one of the four. My favorite? The idea that Coulson may well end up being the Vision. Why? It may be the most controversial rumor about at the minute but in my opinion, Marvel have been setting up Coulson as Vision for a long time, and here's why:
*Who doesn't like Phil Coulson?
The Avengers was a great film but a lot of people have problems with the characters. Complaints such as, "Maria Hill has the personality of a brick" or "Black Widow is only used to bring in more male viewers" are thrown around a lot but Phil? No one complains about Coulson, he's the one guy everyone likes, and if Marvel were going to introduce a non-mainstream character like Vision they'd want to use a well known and likable character. Coulson seems like the perfect choice.
*He's the perfect blank slate
If you didn't know, in the comics, Ultron created Vision to help in his battle against the Avengers. Were it to be revealed in Agents of S.H.I.E.L.D that Coulson as a LMD (Which have been mentioned in the MCU) Ultron could easily alter him into Vision to help him fight the Avengers in Age of Ultron. As well as this, we know Ultron likes to manipulate people, we are also pretty sure that Stark is going to be directly involved with Ultron's creation. Stark was the worst affected by Coulson's death in Avengers and this is something Ultron wouldn't think twice about doing.
*He's trusted by everyone
Everyone in both the Avengers and S.H.I.E.L.D trusts Coulson, most importantly, Nick Fury, even referring to him as his "One good eye". If anyone were to be manipulated and used against the Avengers in Age of Ultron it's gonna be the one person everyone feels safe around, again making Coulson the perfect choice.
So, a lot of people don't like the idea of Coulson becoming Vision, mostly fanboys who want a perfect origin story taken straight from the source material, but we know the MCU isn't really sticking to the source material (That "twist" in Iron Man 3) so what's the big deal? As fans we want to see as many of our favorite characters in added as possible. Marvel have the perfect opportunity to introduce the Vision so let's just sit back and enjoy what Marvel give us next.