I forgot about the Defiant-class...
Yeah, I mention it in my third post, page one. The thing about the Defiant is that it looks not like just a saucer (the rounded front being most suggestive of), but almost like a singularity-squished multi-hulled Starfleet starship in one. It has "separate" nacelles and deflector assembly, and the rear half looks like it could be a more square-like secondary hull from another ship - the
Conestoga or something. It reminds me a little of the
Sydney Class transport, or a Runabout or
Scout or other overgrown shuttles.
I think the idea previously was that starships had different components for safety reasons. You had the main ship (the power core) separate from the crew (saucer) and separate from the warping nacelles. Each component had various safety issues with concerns of explosion and energy field reactions, and each could be detached and replaced for whatever reason (new nacelles, saucer sep, etc).
Before ENT, I imagined earlier starships being more gangly and primitive looking still. The Daedalus was suggestive of that. I imagined earlier ships looking like something out of
2001 or
The Martian or
Babylon 5.
By the time the Defiant came along, the tech was advanced enough where it was safe (enough) to squish in as it was. Also, maybe the Defiant gave up a lot to be as tightly-packed as it was. Maybe not just crew and labs and inhabitability, but, looking at the Sovereign and subsequent huge-nacelled designs, mobility advantages too.