1. Their data storage system where hard drives are retrieved by a manually operated claw machine game.
2. Their data transmission system that requires one to use a Wi-Fi link placed on a dangerous aerial catwalk with no safety rails.
3. Their seemingly lack of off-site backups evidenced by the confidence that destroying the data center will ensure the only copy of the death star plans are erased. Which begs the questions of how did they build the 2nd death star so quickly without the original plans?
P.s. did anyone else, while watching the scene where the heros were searching the Empire computers for the secret file name, think of the line from the Simpsons where Homer says, "I've heard how this ends, it turns out the secret code was the same nursery rhyme he told his daughter!"