I believe one of his rules was also that the bridge should be on the top op the saucer section
...Which didn't stop the designing of ships without saucer sections altogether. A nice balance of diversity vs. continuity emerged, so that we can still tell at a glance when a ship is from Starfleet even though DS9 and ST:FC steered quite sharply away from the TOS Enterprise
shape. It's a combination of shape, components, paint job and pennants, even when no single one of these elements is actually a constant.
Yeah, two nacelles may feature into it. But we had no problem identifying the Kelvin
as a hero ship.
I remember the Klingons were going to in Generations, and the NX-01 got its bridge ripped off in one episode.
Both incidents involved an unshielded ships. Perhaps Starfleet has as much reason to prepare its starships for unshielded combat as the US Air Force has to prepare its fightercraft for battles fought on the taxiways of airfields?