Let's see...
The game would be set on Tatooine between the original and new trilogies for maximum movie nostalgia.
It would advertise an entire planet to explore but it would really only be 15 square miles or so.
The main capital would be Mos Eisley, again for movie nostalgia.
Level scaling Jawas and sand people everywhere.
The Hutt Cartel, the Imperial Forces, and the Rebellion would all have their own guild houses and quest chains. You would be able to join all three at the same time.
Tatooine would be full of random dungeons and monsters.
A few movie characters would show up with their original voice actors for the main plot, which would probably link to the beginning of episode 4.
There would be a space battle mechanic that was hyped to hell but would end up being horribly underwhelming and tedious after you do it once. And then space battles would feature heavily in the main quest.
Somehow there would be an arena in Mos Eisley.
Instead of magic there would be force powers because your character is a jedi for some reason.
It would have all the other flaws of Oblivion. Level scaling, retarded or just nonexistant dialog, a main quest that can be beaten at level 2, completely broken AI, the list goes on.