Would TNG have had episodes like Faces, Resistence, Meld, Deadlock, Tuvix, the Thaw, The Chute, Revulsion, Year of Hell, Hunters, Extreme Measures, or Equinox? What was recycled from TNG? Are you saying that because they're both "Ship shows" that there are stories that could be told on both?
If DS9 was so dark, and so serialized, why then, during the darkliest most serialist season of the show(6) was there 3 Ferengi comedy episodes, an "I hate my new mother-in-law" episode, a "Honey, I shrunk the space shuttle" episode, a mirror universe love story, a holodeck/romance episode an "O'Brien is Donnie Brasco" episode, a "Molly O'Brien time travelled" episode, and another time travel episode about some lady's voice, and an episode about Bashir's genetically modified misfits. A few of these in some ways tie into the war. Many others don't