1970 Dart matching numbers 340 4 Speed

I'm sure part of that "restyling" was to cheapen production costs. Think about how simplified (less parts count) that '70 rear end is compared to the '67-'69 design. The front grille is all plastic too, another way to make the car cheaper to produce. The '70s-up don't look "ugly" to me, just simplified, and not quite as interesting as the earlier cars.
By 69 the dart body style had basically been the same for 3 years and somewhat dated. Though I'm sure some changes were made to reduce costs It was also a Time when parts could be taken to the next level through molding that would cost a fortune to try to if you even could reproduce with metal parts my 70 grill is original it has held up extremely well it's amazing so questioning its integrity is somewhat moot. It is much more detailed and complex than any other dart grill before it in my opinion. Also the tail lights in the bumper was the trend that Mopar had moved to just look at the super Bee for 70 roadrunner for 71 and some as mentioned do not care for the tail light in the bumper look ok but the trunk deck how it marries to the bumper looks really good compared to previous years.