Captain's mess

In TOS design logic, ships need two warp nacelles spaced left and right

nacelles arranged like this has mostly been followed for the rest of Trek.

I'm aware. There has never been a requirement for a saucer, even in TOS, and I did not say that. But the nacelles are arranged at the extremes of the ships, even in compact designs in later Trek, which does follow the established logic. Vulcan rings are a rare exception to the left and right nacelles - covered under the word "mostly".