A lot of those trailer shots are just glamour shots. For instance Jyn vs Tie Fighter, Jyn in tunnel, etc
Sure but the missing beach narrative and the larger Forrest Whitaker plot were in most of the trailers. The latter being something that might actually still fit what they ended up with.
Huh? All we got were one liners from Whitaker in the trailers. Beach narrative was probably just a more complicated setup for the complex, which was probably deemed to add nothing to the story but time and complication.