Re: USS Copernicus, NCC-640 or 623?
I like that idea too, as Mastercom did something similar with the 1800 series cruisers (Tikopai class). They had originally been envisioned as refits/upgrades of the basic Constitution class during the TOS era, as seen in FJ's work, but owing to various delays and other designs did not actually see service until the movie era with more advanced technology than had originally been planned.
"My dream is to eat candy and poop emeralds. I'm halfway successful."
Catbert, Evil Director of Human Resources