I think the beauty of DS9 is they started many threads but were able to tie up a lot of them nicely and still leave a lot of great stories to be told. The ending of the show was wonderful, and they certainly left a lot of doors open for writers to continue the story in the books! I've heard a lot of great things about them and I hope to purchase them someday and read them all.
Have to say, a lot of these topics are really cool and more depth to each story would be really interesting to read/watch. I've read a few of the DS9 books and really enjoyed them, and keep meaning to keep the story going by reading more. I think more Benny Russell would have been good though, probably my all time favourite Star Trek episode of any series and think there was plenty more available there to tell. As Roddenberry said once, there's so much out there for ideas and stories to tell, possibilities are endless.
How cool would it have been for the last episode to have Mark Alaimo and Jeffrey Combs grabbing a handful of documents from Benny, throwing them in the trash...then a few minutes later, a young man with a woman on his arm walks by the trash and the image of DS9 catches his eye. He stops, picks it up, starts reading the text and says, "Say, this writer is really on to something here! Now if we make it a space ship instead of a space station, take away the long story arcs, make it more about exploration and change the characters, we'll be golden!" Then the woman with him says, "You're crazy, Gene!" Fade to black. I'M ONLY JOKING, GUYS! Seriously though, I'm one of those people who really liked what they did with the Benny Russell scenes. I, too, wish they did more, but there's no doubt there would have been hell to pay if they did!
I'm glad they didn't side with one of the original plans to end DS9 with Russell outside a Hollywood studio with a Star Trek script in his hand, as people have said in interviews, would have completely lowered the value of the whole franchise.
Seriously? No mention of Hard Time? A senior staff member is incarcerated for 20 years... TWENTY FREAKIN' YEARS and is then released. He can't handle it to the point that he's ready to blow his own head off with a phaser. There's no memory erasing or anything at the end of the episode - He supposedly never forgets it - but it has NO follow-up... ever. That just burns me. And yes, he probably dealt with it off-screen. Fine. But at least a mention of "How's your treatment coming along?" would have been nice, considering how far they went with it. But by the next episodes, it was back to work, business as usual. Big fat reset button.