I think my biggest regret is that Paramount didn't want to give them the money to make the Tsiolkovski Rick had designed, so they had to re-use the Grissom from TSFS. They didn't even change the markings on the model! Even at '80s TV resolution the NCC-638 is clearly visible in several shots, plus the outdated pennantry. In my headcanon, every instance of that model in TNG+, and every use of the term "Oberth class", refers to the ship Rick designed, but could never get them to spring for. Came closest with "The Pegasus", but alas.
Also, the Hood is NCC-2543, the Melbourne is Nebula-class, and get off my lawn.