1. Kill off Keiko O'Brien, never cared for the actress at all. Then pair up O'Brien and Kira, they had much better chemistry than she and Odo did.
2. No Worf, I had enough of the Klingons on TNG I didn't need any more of them on DS9. All it did was ruin Jazdia's character.
3. Instead of Jake working for the Federation News Service, have him work for Cassidy Yates to gain life experience.
4. No Ezri Dax, instead have the Dax symbiont go to a male host and have Nicole as a Romulan liaison.
5. No Rom as Nagus, instead have Isska as Nagus.
6. End the war a few episodes earlier and have Bajor admitted to the Federation Then have Sisko fight Dukat and his disappearance will be bittersweet to Bajor as they celebrate Federation status and lose their emissary.
AND... NO "female" Quark!!!
That was a BAD idea, the mother of all.