Star Trek: Deep Space Nine was the fourth Star Trek series and entered production in 1992. It was broadcast in first-run syndication from January 1993 until June 1999.
The decision to set the series on a space station, rather than a starship, spawned when Brandon Tartikoff originally approached Rick Berman about the show, in 1991, and specifically said he wanted it to have a format that was new for Star Trek but was classically western; if The Next Generation was Wagon Train in space, Deep Space Nine was to be The Rifleman in space – a man and his son coming to a dilapidated frontier town on the edge of known civilization.
Star Trek: Deep Space Nine is the third live-action Star Trek television series. It entered production in 1992 and was broadcast in first-run syndication from January 1993 until June 1999. The series is set on Deep Space 9, formerly a Cardassian space station, but at the start of the series...
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So, DS9 was developed between 1991 and 1992. Sounds like episode inspiration ideas would come from this time. That includes "The Wounded." However, it makes the most sense to me that the first episode intentionally intended to connect to DS9 was "Ensign Ro" and they decided then to use the Cardassians.
Was the original idea to use Romulans or is that just wishful thinking?