It's an interesting question. One thing to remember: this isn't just reshooting -- they're not finished with the movie. It's not like ROGUE ONE where they put a completed cut together, didn't like it, and then hired someone else for reshoots. Here, they may rework some things that have been filmed, but filming isn't completed to begin with.
I did not realize Lawrence Kasdan had so much to do with this movie. He wrote the script with his son and is a producer -- Lord and Miller didn't write it, so that changes my view of this a little bit. It could be that Lord and Miller were riffing or improvising or pissing Kasdan off in addition to Kennedy -- who the hell knows. Maybe one day we'll find out. Kasdan naturally would've been the go-to guy to direct it, but DGA rules apparently prohibit that from happening, so we'll see how it shakes down.
Tony Gilroy DIDN'T get credit for directing new scenes -- lots of them -- on ROGUE ONE, but the circumstances are different here. My guess is Howard will end up being the only credited director unless there's really a substantial amount of Lord/Miller's movie left in the final cut. IMO I highly doubt Howard would've taken this unless there was lots of movie left to film and/or reshoot in the first place.
Here's the interesting part of Deadline's article on this:
http://deadline.com/2017/06/ron-howard- ... 202118193/
The Lego Movie filmmakers dropped in a testy exit after an inability to recover from creative rifts between them and Lucasfilm chief Kathleen Kennedy and Lawrence Kasdan. He wrote the script with his son, is exec producer, and a backbone of Jedi lore as the scribe of early Star Wars films The Empire Strikes Back and Return Of The Jedi.
The exit of Lord and Miller shocked Hollywood and indicated that directors are becoming as disposable in these tentpole blockbuster sequels/spinoffs as screenwriters have always felt. The whole episode is vexing to the DGA, and it will remain to be seen how the credit situation gets handled. You always hear about directors being shoved aside on problem films — World War Z among them — but it became an open secret that Tony Gilroy directed extensive re-shoots that he wrote on the Gareth Edwards-directed first Star Wars spinoff Rogue One. The credit issue wasn’t tested there; Michael Clayton helmer Gilroy was paid millions of dollars and Edwards remained the credited director on a film that turned out to be a crowd-pleasing success that crossed the billion-dollar mark in worldwide gross.
The DGA, under what is commonly known as “the Eastwood Rule,” prohibits an actor or producer from firing a director and taking over. This occurred after Clint Eastwood had a beef with director Philip Kaufman on The Outlaw Josie Wales, that not only had to do with the film’s tone, but also an actress — Sondra Locke. This complicated the idea that Kasdan would take over, despite credits that include The Big Chill. The credit situation is a matter for another day; Disney’s priority is to get finished a film that has high stakes because of the beloved nature of the rogue Han Solo character.