For me, most of the design failures in the PT are because Lucas or whoever was in charge of story and design wanted to continuously do homages to other things, maybe hoping that duplicating that approach would make the newer films as successful as the older ones. For example, having a Hammer Films actor appear in the AOTC, Commander Cody being based off of a 50s character Commando Cody.

So visually, the 1950s USA reference with Dex's Diner took me right out of the film instantly. That had no place in the SW universe.

Then there's the big lumbering, 1950s styled robot/alien in robot armor Wat Tambor who represents the Techno Union. It seemed more like the producers were being cute then trying to actually insert characters who seem like they would exist in this universe.