It's not 3D, it's 2.5D as they say.
Ships can't go up and down, except to avoid eachother so they don't crash.
Starfighters are abit more free to roam around.
The game starts
2 years before ANH, so I wouldn't really consider it set between Ep III and IV.
There will be a demo, I think scheduled for release in November.
As for title, I would guess you would be a Supreme Moff (if you were Imperial, but why wouldn't you?
), though that position only existed as a potential rank around that time, and none is known to have had this rank.
My guess is Grand Moff Tarkin would prolly have been rewarded with this rank had he not died on the Death Star, and if he had managed to destroy Yavin IV.