I stated something related on another thread and wanted to add some of that info here, as it relates to the question of warp drive limitations:
January 2003, Volume 3 Issue 09. Pgs. 98-101, written by Rich Sternbach, gives the design goals of the Constellation-class, and it includes a deck-chart cutaway.
It is specifically stated this layout was to meet 4 goals compared to the Constitution refit: 25% more crew, 25% more cargo, same speed rating, fit in existing docks.
Amazingly, this vessel is described as looking the way it does for a reason: to have more labs and crew in a vessel of similar size.
This design approach helps justify a design like the Kelvin, in that it is not really bigger than a Constitution class ship by livable internal volume if the upper secondary hull is mostly open hangar deck, and the nacelle contains basically only engineering and mechanicals. The seemingly large saucer is possibly only 1 deck tall in the middle, and is designed for the crew to have lots of labs and quarters, without an arboretum, pool, large cargo bays, etc. Maybe it needs a big hangar deck because it basically warps directly into a system, the crew spreads out in shuttles to explore, then rejoins the ship to warp away. It's like this ship is sort of a mobile base. That approach would change to a more detached vessel that could do more maneuvering on its own, then later the Galaxy class returns to being a like a base, except this time, it is maneuverable too.