Here's the asteroid field sequence from The Empire Strikes Back:
And here's the Battle of Endor (just the space parts) from Return of the Jedi:
So what's so abnormal about this? The Star Wars movies, all of 'em, are full of lots of great space flying and whatnot, from Anakin's podracer all the way to Lando blowing up the Death Star II. So what's so special about flying the Millennium Falcon? Well, look at the ship -- where every other ship in Star Wars has its cockpit nicely centered, the Falcon does not. Its cockpit is way over on the starboard side (from the perspective of the pilot), so when flying it, ninety percent of the ship's width is to the pilot's left! Now, since the Falcon is originally a freighter, this probably isn't that big a deal, when you're using the Falcon as such -- as a ship to ferry stuff from one planet to the next. But if you're going to engage in high-speed derring-do in the middle of an asteroid field, or if you're going to fly the ship through the superstructure of an enormous space station at very high speeds, to be able to negotiate those tight spaces while being instinctively aware of your ship's lopsided design, well -- that makes you an even more awesome pilot than anyone ever believed.
Clearly the Falcon and its class of freighters weren't designed to be used in the way that Han Solo and Lando Calrissian use her, but as I've noted before, design and use aren't the same thing.
(BTW, in ROTJ, does anybody else besides me ever feel a bit sorry for that last TIE fighter pilot? The one that follows Lando and Wedge all the way to the reactor core and then follows them almost all the way back out again before getting killed in the fireball that's swallowing the Death Star II from within? That's gotta suck. I'm sure that guy wasn't even thinking of trying to shoot down the Falcon once he reached the core; he's probably saying to himself, "Oh shit oh shit oh shit OK I did it once before I can get through this again oh shit God I wish that f***ing freighter would move his ass otherwise I could get the hell out of here wow it's getting hot in here oh sh--!")