To me, it looks like a ship of the line. Kind of likening it to steam railroading, where you had most attention on the crack passenger trains of the day (and those locomotives garnering more attention, like the Constitution Class being the top of the line starship) but the day in, day out, workaday freight locomotives or switching locomotives not having as much attention paid to them (the Discovery, etc. being reliable and serving out there, but not seen as much or paid much attention to).Yeah, in addition to the shuttle, there was the Romulan Pird of Prey, which according to early canon was meant to have round nacelles as a nod to Romulan espionage and reverse engineering of Starfleet tech - and the remastered TOS Medusan ship which was also meant to be Starfleet tech - but we never saw another Federation starship alone the lines of the Ptolomy or Saladin, so didn't want to push the evidence too far.
I think the reason I immediatly loved the Discovery so much is that by consciously going back to a 70s paradigm in terms of design, they immediatly make the ship look more like something from 'an era of it's own':
What these bulky industrial designs do is serve to ground the show in a different technological era from the flowing organic curves of TNG - and also from the less blocky TOS and TMP era - it's purely symbolic, as by the 23rd century if tech progresses as it is doing now, I doubt we will have any constraints on shaping things - but the symbolism is strong - the design looks like something more primal like the Nostromo from Alien or the Sulaco from Aliens or the Discovery from 2001 - a ship of exploration, a platform, a space rig.
To me, this also serves as a platform to say that Starfleet designs start to merge elements we see on Discovery and TOS Enterprise, evolving over years and eras to the Galaxy Class.
