Jutland would be great. There is so much data known about that battle the movie would practically write itself if sticking to history was the goal.
Coronel would be also interesting. Ever wonder why one of the first battles of the First World War happened on the South Western coast of South America???
It is a very interesting story
Both of these would be great movies.
I also would love to see a movie on the Commerce Raider Emden. After reading the exploits you have a hard time remembering that this is fact and not fiction. What adventure!!