It's worth considering that at the moment this spacecraft design is probably still reasonable in cost effectiveness. The good hull material roll gives some stretch after all, and while that was some what expended in making a very large new generation craft, the extra systems that can be held with in it would probably balance that out and give a pretty reasonable rating overall.
Basically the current benefit of this design is that it's heading towards being a very tough bruiser, it's much thicker then previous designs while having a very tough hull material, making it much harder to destroy critical systems. For instance the big secondary hull means you have to punch through quite a bit of tough hull material to reach the warp core now. Also due to the quad nacelle arrangement, one of the few critical components that couldn't be hidden deep inside now has redundancy, making it basically even more capable of tough stand up fights. This all helps greatly offset any drawbacks in maneuverability in the current structure while greatly benefiting it in a prolonged battle. Combine that with enough space to make a good science craft as well, and you have a not bad outcome.
Of course making everything so big, is not cheap, but I at least think that the gained capabilities from it together with the good hull material roll let it average out to a highly acceptable trade off between an explorer and a battleship in current setup. And as such would have a good chance of having a reasonable number of ships made to fill those two tasks in the roster.
This is probably why a fair few people kind of want to hold off on further experimental work, as if you just finish up what you currently have it will most likely be a reasonable success. While any additional expensive experimental technology would create the risk of a failed roll, causing the current balance to breakdown and its cost effectivity to become less good.
Admittedly if one did manage to get the experimental engine tech to work well, the craft would likely reach S rating on tactical with out to big a cost increase and thus justify the craft becoming more expensive. But that's a pretty substantial if. It kind of depends on how much one feels on gambling further when one might already have a modest win on their hands.
