Well, it's official. Look for this to hit the trades soon - Christopher Markus and Stephen McFeely will write Avengers: Infinity War I and II, keeping them teamed up with their Captain America: Civil War and Captain America: The Winter Soldier directors Joe and Anthony Russo. You were wondering who would handle the MCU once Joss Whedon was gone? Why, it's the guys who knocked it out of the park with Winter Soldier. I had reported that they were in talks before; it's a done deal now.
Markus and McFeely have been a major part of the MCU from Phase One, writing Captain America: The First Avenger. They also wrote on Thor: The Dark World and created Agent Carter for ABC. Having them be there to wrap up Phase Three (and the whole MCU? Kevin Feige's contract is going to be up around 2018/2019, and while they have a Phase Four planned - with films through 2021 on the big white board - Infinity War makes for a nice place for everybody involved to step off and wave goodbye) makes a lot of sense, and reaffirms Marvel as a studio that works like the old Marvel Bullpen, with lots of in-house people doing a lot of the heavy lifting.
What this means in the immediate run is that Captain America: Civil War is even more likely to set up a lot of the stuff that will pay off in Infinity War - after all, the same team is making all three films. While Thor: Ragnarok is supposedly taking the universe-shaking role that Winter Soldier had in Phase Two, I would expect Civil War to help redefine the landscape that will lead to Infinity War.
I couldn't be happier - Markus and McFeely are strong writers, legit fans of the properties and they work well with the Russos and Marvel. I keep waiting for Marvel to finally fuck it up - I really thought Ant-Man and the Edgar Wright debacle was the end - but it looks like they have my goodwill all the way through 2019.