It's not just you, and it's not just Mopars. I have a '67 Buick with some of the same issues, and I've seen it at the car shows too (not the concourse shows, the "driver get-together" types.)
In fact, IMHO, one of the little things that makes some of the concourse restorations and show cars sometimes looks "not quite right" -- that funny little "something" you can't quite put a finger on, is that panels are too straight, lines are too perfect, and paint is too flawless.
Like Marylin's "beauty mole," it's often the little imperfections that make it right.
70rr-Brian mentioned that panel alignment was an afterthought, and that's not entirely the case, nor is it entirely untrue -- but the fact remains that the cars we so love and covet today, were never intended to be collector's items 40+ years ago when they were made--they were designed to be consumer items....and they were intended to be consumed (i.e. used up). It's actually interesting to me exactly WHICH cars end up being collectable and "interesting" vs. the ones that are just a flash in the pan.
There are and always will be a few cars that start off "special" and will always be such, but to me the truly interesting cars are the run-of-the-mill production cars that just "stick in your mind."
So don't worry too much about the panels that don't quite line up, or the sheet metal that's a little warped in the lines--it came that way, and it's what makes the car "REAL!"