A pretty interesting video about Solo, Rogue One (and more) and what the ‘directed by’ credit actually means.
Interesting, I’ve never read DGA rules or anything but what I’ve heard is that Lord & Miller actually could have fought for the final credit if they wanted, but of course elected not to.
Apparently Howard reshot 70% of the film (at least that’s the number on the streets these days). When you factor in that Lord/Miller did the entirety of pre-production, you could potentially argue that the film is half theirs, half Howard’s. But it’s easy to see why they wouldn’t want the final credit.