I'm not saying that there isn't a level of producing control (obviously there is, and should be. It'd be insanity to just let it be a free-for-all) but that doesn't mean there isn't directorial freedom.
I've heard it alleged that the
Guardians movies are unique in the franchise in that the previz department doesn't start their work until Gunn's script is complete, whereas with all the other productions, previz and scripts are worked on simultaneously, sometimes before a director is selected. Not 100% sure about that, or if there are any other exceptions, though.
Another Cretton movie is good news, sure, but I'd rather it was another Shang-Chi movie.
The wait for a Shang-Chi sequel is indeed maddening. From
Iron Man to
Endgame, there were only three years (2009, 2011, and 2014) in which Tony Stark wasn't on screen (and all of his appearances were major roles), and from
The First Avenger to
Endgame, there wasn't a single year in which Cap wasn't on screen (though, okay, Evans' cameo in
The Dark World wasn't technically Cap, and he was only a cameo in 2017's
Homecoming). From
Thor to
Endgame, there were only two years (2014 and 2016) Thor wasn't on screen. These consistent appearances from the major Avengers were a fundamental part of the franchise's forward momentum.
Meanwhile, Shang-Chi is the biggest single character the MCU has introduced since
Endgame, and he was last seen three years ago, with no known sequel date, and not even a cameo since. WTF!