Shanerjedi:
Add Ben on a speeder and have him give that dragon call and then have him swoop in do a CG backflip off the bike, and then whip out his saber and start taking out Tuskens.
Now you know as well as I do that some people will think that's a fantastic idea.
But you've got me thinking and I'm going to go back and improve some classic movie entrances in a similar fashion...
Remember the brooding, shadowy entrance of Max von Sydow in The Exorcist? Not any more you don't. That old fella is gonna come flying in over the rooftops on a speeder bike up to those gates, grinding that engine and scaring the shit outa that demon. No mysterious entrance for Father Merrin any more, no sir. Now we know he means business.
Mary Poppins? Umbrella? Haha, oh no, no, no, no, no.
Ghost:
Could Luke and Bens conversation be moved to later in the movie somewhere?
You can try putting it at various points in the movie, but it has to come sooner than later. Either at the start or roundabout where it is already. If it can be made to work, then the beginning would help sell Luke's plausibility as a Jedi.