I assume it will be after the events of Rouge One, but before the battle of Hoth.
Main factions being the Imperial Navy/Army and various Rebel Cells/Full Alliance. Or Freelancers, Bounty hunters, civilians, traders etc..
Would prefer Legends over Cannon due to the amount of content and ability to expand.
Would be nice to have a running plot of some kind and all characters more or less on the same side, and in the same place. Cannon characters such as Luke, Admiral Thrawn, Vader etc to a minimum.
Definelty after the Rebels treaty with Mon Calamari and the addition of their capitol ships to the battle.