DS9 gives us war. No other series gave us a lasting full-scale war to see, and DS9's enormous fleets, million-man armies, and vicious realpolitik was something of a shocker.
DS9 shows large fleets, short ranges, and is notorious for scaling issues regarding the Defiant and the Deep Space Nine station itself.
The Deep Space Nine
Encyclopedia and Lexicon is a potentially useful fan website. The DS9 scripts are also
Ex Astris Scientia
has an overview of DS9 era scalings, as well a separate article on scaling the Defiant.