I'm not so sure about "not enough Imperial presence". One of the things the films deal with thematically is the Empire's arrogance, that just the fact that they're there should be enough to scare people. To that end, they don't send everything they've got to every battle, just what they think will be needed for the situation. All they expected to be escaping from Hoth was a couple of slow, bulky transports, a few fighters and the Falcon. From the Empire's perspective, the Falcon was the only one that was a challenge - the rest were fish in a barrel.

As far as all the "ship travel direction" stuff, that feels like it's getting nit-picky. If you've ever tried to take real photos of objects staged a certain way you know that camera angles, shapes and perspective can play tricks on you if you're not careful. I read that when they first started filming the Enterprise D for Star Trek:TNG, the oval saucer was throwing them off - they had to film the ship from weird angles and going in illogical directions to correct the skewed perspective to make it look like it was going straight on screen. Could be something similar happening here.