I just read Reid Jones' article regarding this. Great read. So I'll just throw in my one idea.
Captain America: Secret Avengers
Kevin Feigie said that the title would make fans go nuts. So I think this is the title. The title alone will tell us if we will get Civil War or not. Secret Avengers does confirm Civil War doesn't it? What else could make fans go nuts?
At the end of Avengers 2, Cap is said to have assembled a new team. After reading Alisha Grauso's Civil War post, I feel this route for Cap 3 is possible. Cap will probably call this team New Avengers and then it will later evolve into Secret Avengers. In the comics, Secret Avengers was started by Steve to fight the Superhero Registration Act. I imagine that this team helps him find Bucky and fight baddies along the way. I really see this happening. Here's why: In Reid's article, he had many possibilities. I think Marvel could put em all in and make it work.
It has been rumored that Chris will come back after Avengers 3. So he definitely won't die in Cap 3. I'm sure that Cap 3 will be the zenith of his acting career.