Another thought I've had, though I don't know if it interests you or could be pulled off, is that in the novel, and presumably in the script given to ADF to novelize, Luke made two runs through the Death Star trench. The first kept him out of reach of Vader's squadron due to their rapid speed, but it obviously failed for the same reason and they had to make the run again. Though you still want to make an enjoyable, well paced movie, it seems this could be an interesting addition. As an additional resource, the Star Tours footage includes shots hardboiled useful, including a different shot of entering the trench, flying down the trench, a little dogfighting with TIE fighters, etc. Food for thought, anyway.