For all intents and purposes, though, it's the same peacetime design, only that the Enterprise-D belonged to the first batch of ships and the next batch featured some improvements that would be expected in any design after a few years of service (although on a case-by-case basis). I don't think starship designs are static--they evolve over time and incorporate new technologies and ideas along the way.Sorry for jumping in late here. Real life intervened.
But my sense has always been that the Galaxy-class, as originally fielded in 2360s, was a powerful and respectable vessel. Certainly the most powerful of any other class of starship then in Starfleet service. But it was, in my view, not as powerful as it could have been. Rather than being as powerful as the spaceframe and power systems could make it, the ship was probably designed to be as powerful as Starfleet's experts felt it would need to be.
Recall the situation around the time the Galaxies were entering service. A peaceful, allied Klingon Empire. The Romulans in total isolation. No contact yet with the Borg or Dominion. Some fighting with the Cardassians, sure, and other powers, but no one that really could rival the Federation in an all-out war, if it came down to it. The Galaxies were designed in peacetime, and I imagine that their tactical systems were designed by people thinking, "OK, well, how much firepower does this thing need to make it the strongest ship in the fleet and make sure it's competitive with anything else operating in the region? Let's figure out what that much firepower is and go with that."
But, in short order, the Romulans were back, the Borg were around, the Klingons went apeshit and the Dominion showed up. I think the Galaxies we saw kicking so much ass in DS9 were the ones that Starfleet had outfitted to maximize the combat capability of the class, rather than just meet the bureaucratic requirements of the design tender. And that was probably a very substantial increase in firepower indeed (and was probably also done to most every ship in Starfleet that was capable of it).
I absolutely agree. I think your theory is by far the best one I've seen. The Enterprise-D was a peacetime ship, whereas the kickass Galaxies we see in DS9 are true warships.
Had the Enterprise-D not fallen at Veridian III, she may have been upgraded and might even have been in the process of being so at the start of Generations if the new bridge module (and perhaps even a new stellar cartography lab) was a first step.