I know it isn't listed, but what about the Nebula class? It's basically a more compact Galaxy so it could have a powerplant equal to the Galaxy to power its shields and a pretty similar weapons loadout. Throw in that oversized triangular pod, which has at least one torpedo launcher, it could be better armed than the Galaxy.
I haven't seen "The Wounded" in a long time, but was there any comparison between the Phoenix and the Enterprise that could be used as an example on how the Nebula stacks up against the Galaxy class?
I think the intention was that the Phoenix was a smaller ship, despite the Galaxy parts being reused. Later, with the CGI model that directly used the Galaxy saucer, with all the windows intact, you have to retcon that it always was a counterpart to the Galaxy, like the Miranda to the Constitution.