The Federation had a huge advantage in the Space front. A Nebula class was more then enough to cause problems for the Cardies
The various appearances on screen of the
Nebulas fighting Cardassians would seem to suggest otherwise. The
Phoenix only took out an unknown warship and still took heavy damage from the single salvo it got off. Likewise, the
Honshu was easily dispatched by the Cardassians when carrying Dukat and Sisko. Beyond that, we have no information, at least not that I can recall, that says the Federation was running roughshod over the Cardassians in space.
The Federation never took it to them like a invasion, attacked huge sectors, core worlds, and beyond.
What? Setlik III was most certainly an invasion. And in any case, just because your core worlds aren't attacked does not mean it's not a "real" war. The continental United States was not attacked (I'm not counting submarine shellings or hot air bombs) during WWII yet no one would dispute that the US was on a full war footing and suffered substantial casualties.
The Excelsior was a Battleship at one point then turned into just a cruiser.
I'm sorry but do you have a source for this? If the
Constitutions were, canonically as per Star Trek III, heavy cruisers then I have a hard time believing that the
Excelsior was considered a "better" ship than that. On top of that, "battleship" is hardly a term I can see Rodenberry, who was very much still in the middle of things when Star Trek III was filmed, signing off on. It's just not a very appropriate term for how Starfleet was viewed.