Babel (OB 24 Jan. 1993) score: 5

Whereas TOS made a "Journey to Babel," everyone comes to DS9.  

Jaheel will try to ditch multiculturalism

Virtually the entire station catches (viral) aphasia, making communication impossible, in a borderline episode that I've downgraded slightly. 

From 2003 notes: "the main problem is the episode isn't about anything."  

In 2008, I was less literal: 

"every society's held together by common beliefs, here symbolized by language.  Disrupt these, you divide and conquer."  

Then and now, it seems unfortunate the inventor of a weaponized contaminant is named "Dekon."  Maybe the writers were distracted: the aphasia has little to do with Bajorans vs. Cardassians.  Instead it materializes cultural anxieties, as the fractious station reaches breaking point.  The message (for the U.S.) is still timely: is a common language enough?  Note also the virus begins in the replicators, food being central to cultures and, sometimes, to culture clash.

Themes aside, the flaw is more prosaic: the aphasia scenes don't work.  (Per IMDb, director Paul Lynch never returned to Trek after DS9's first year.)  That leaves a hand-me-down version of "Darmok," partially redeemed by Odo/Quark interplay.  Whereas Brooks and Visitor still seek their character, Auberjonois and Shimerman are up-to-speed.