If one reads the DS9 format documents, one gets the picture of it being a series much more broadly defined than the one we got. What we saw in the bible were the basics: Starfleet officers on a remote outpost, the Wormhole providing the traditional aliens-of-the-week, Bajor and Cardassia as a backdrop to provide further story fodder. Season 1 is defined by this lack of cohesion, seeming to throw elements of all of the above at the wall to see what sticks and what doesn't. By the end of the season, and certainly into Season 2, I'd say that they had a
very clear idea of where they wanted Deep Space Nine to be. The three part storyline beginning with "The Homecoming" basically set out where they intended to go from here.
From memory alpha:
At the end of season one, Michael Piller directed the writing staff to concentrate on the show's uniqueness for season two and to let go of the links to the universe of The Next Generation. As such, for the season's first episode, the writers chose to do a show which couldn't be done on TNG, a show which was completely unique to the world of DS9. (Star Trek: Deep Space Nine Companion)
It was a very conscious "line in the sand".