It's like POP! did a TOS Enterprise.
Yeah, the term "super-deformed" has been used for the J. I can't decide if it loops so far around that it's actually cool or not, but it hardly matters outside of the MMO, the actual on-screen time is minimal.
The size trend they were on was clearly not sustainable for anything pretending to be an exploratory vessel.
I mean, the D suffered from enormous mission creep and some design-by-committee problems as well that left it as a jack-of-all-trades and master of none. It was meant to serve as a showy flagship for peaceful diplomacy
and sport enough combat potential to act as a warship to defend itself and others, while
also hypothetically being able to conduct long-term scientific research missions with noncombatants and their dependents along
and having the cruising range and warp speed to be useful in an exploration role
and then having some role in planetary disaster relief operations
and fleet command-control-communications functions. All of those are things Starfleet wants and (maybe) needs, but putting them all on one big, expensive platform was far less useful than spreading them over multiple more specialized hulls would have been. They could never build enough Galaxies to have one everywhere that their functions were needed, and the ships themselves were so complex that anytime they needed upkeep and overhauls it was a serious loss of fleet-wide capability.
They're just a boondoggle, impressive as they were. The ones that survived the Dominion War were probably massively rebuilt for more specialized roles that could take advantage of their huge hull volume and powerful engines, which probably meant a shift toward the actual long-range exploration & field research role the initial designers may have envisioned.