Actually Stargazer engineering looks quite close to the Movie Constitution one. The swirl reactor from Voy is actually based off the one seen in TMP and TWOK and given its canon that Stargazer was a very old ship its probably got the same design in both universes. Design wise it makes a lot of sense since the Empire is very short of resources (having only one system) and the 'Gazer probably isn't getting regular refits (or likely any kind of refit actually).
I'd assume the Galaxy is the last throw of the dice, one last design of super ship to try and break back out in to the Galaxy and start trying to retake it. Of course this being the Empire it might actually be the getaway ship for the Imperial government while they leave the rest of humanity to death or worse at the Alliance's hands. Which sadly would justify the Empire being fully "gone" a few years later in DS9, it just died a bit later than we thought it did when Picard left it to die.
I'm still enjoying this series so far be interested to see where it goes from here.
