Maybe I just haven't seen it, because i'm sure there had to have been at least some.. but has there been discussion about how people feel about Whedon leaving? I don't know for sure but i'd imagine they would keep him around the MCU as a sort of consultant since he's had such a huge part in building key pieces. Remembering how great an experience Avengers was and seeing how promising and in the same vein AoU is looking, i'm kind of bummed he isn't doing Infinity War. I know working on the same material can get stale but I figure he would at least put a cap on it by finishing the trilogy of phases, or the "Thanos" arc i guess. The Russo Bros are probably one of the better choices since Winter Soldier was my favorite Phase 2 film by a wide margin, but going from a solo film to a very effects heavy/action setpiece laden team-up film is an entirely different beast.
Also, if i remember right, it was Whedon's idea to introduce Thanos so it would have been cool to see him have fun with the character on film.