False dilemma. The fact that the rate of technological change that we see in the Dominion war is slower than it was during WWII does not mean that R&D is deficient. It's just as likely that the level of technology that the powers in the AQ and the Dominion is at a stage where the technology is not developing as rapidly as it was during WWII. Note also that it was a third of the length of WWII. You use the example of new designs of Soviet and German tanks, but which party in the Dominion war actually introduced a class of ship they hadn't been using before? The Dominion.For fuck's sake, just take a look at WW2, where there was a regular Lensmen Arm's Race between the factions for the whole duration of the war, culminating in the deployment of a city-busting nuclear bomb. In the Dominion War it's mostly the Alpha Quadrant powers who step-by-step dismantle the enormous advantage the Dominion held over them at the beginning. The Dominion never manages to counter this process in any meaningful way which shows their R&D is sorely lacking. Just look at how quickly the AQ managed to overcome the Breen superweapon while the Dominion struggled to breach Sisko's minefield, a technology that was invented more or less on the fly.
Contrast this with the ever-changing tank designs the Nazis and the Soviets threw at each other whenever one side had the upper hand for a moment.
Now, you talk about the Dominion's eroding advantage over the FKR alliance almost as if it it was two equal levels of technology and one simply out R&D'd the other, but it was nothing of the sort. The Dominion had the lead to begin with, and the Federation caught up. With both the polaron beams and the Breen weapon, the Federation had a captured Dominion ship to study and to find countermeasures. Contrast that with the minefield, which was specifically designed to be a bitch to take down after the station fell, and Sisko destroyed the station that had been coordinate the deployment. No, what we see is exactly the kind of convergence that you'd expect when one side goes in with a technological advantage and the other has access to their technology.
None of those things are true. The Battleship was deployed as both a front line combatant, as we see in the Battle for Cardassia, and also outside the heart of Dominion territory as we see in Valiant. So we've gone from never before seen ship, to front line combatant capable of long term operations on its own in *at most* 2 years. That's exactly what I'd call successful R&D.Also, the Battleship? Yeah, such a successful design that it was only ever deployed deep within Dominion territory and at the end just as a stationary weapons platform. Successful R&D looks different.
Your explanation is unnecessarily contrived. They had it all along but they didn't bring it with them to the Alpha Quadrant, but then they started building them vs new ships is new. My explanation is simpler.EDIT:
They did build ships in the AQ, so just because they didn't bring one with them doesn't mean the design is new.
No, that's evidence that the Dominion was in a desperate situation. It's not evidence that the installation of the Breen weapon was driven by that desperation rather than its undeniable usefulness as a weapon. Moreover, there's nothing in the episodes in which it appears that shows the exploitation of the weapon as being counter to the Dominion's usual way of doing things.The Founder calling for a general retreat right after the AQ powers manage to nullify the effectiveness of the weapon should have clued you in...