I don’t understand why they feel they need to have some 10 year plan figured out before they even release their first movie. That’s not even what Marvel did. Marvel didn’t have IW and EG planned out when they were making the first Iron Man film. Hell, they didn’t even know that they would be building up to Thanos until after The Avengers already began production. That’s why they had a placeholder actor for Thanos in the mid-credits scene. It was a relatively late decision, so they didn’t have time to cast a big name.
Gunn and Safran’s plans seem way too ambitious for their own good, especially the part about how they want the same actors to play these characters across film, animation and video games.