How about doing away with any conflict in DS9?
-- After the 50 years Collaboration between Cardassia and Bajor ends, they generously gift Terok Nor to the Bajorans, seeing no further use for it. It was a beautiful and fruitful time, but the Cardassians feel it is time to move on. Major Kira is sorry to see them go, but she can understand and emphasize with the Cardassian stance on the matter. Gul Dukat even offers her to become his mistress, telling that she will want for nothing on Cardassia, but while she gracefully declines, she still appreciates the offer.
Enter Benjamin Sisko, who wanted a new challenge after participating in the Borg Cultural Exchange Program. He turns out to be the Emissary. Benjamin has no problem whatsoever accepting the wormhole aliens as Prophets, and neither does Starfleet have any issues with his dual role; all the admirals laugh, clap him fatherly on the shoulder for being so fortunate, and tell him that in forthcoming cases, of course Starfleet interests can take a backseat to those of the Prophets. Benjamin and Quark encourage Jake and Nog to hang out with one another, knowing full well that this will only culturally enrich them.
About halfway the season, they meet the Submission - a Gamma Quadrant empire that loves to submit to powers of other quadrants, especially from the Alpha Quadrant. They're slightly disappointed when the Federation isn't interested in dominating them, but the two powers get on famously in no time. Odo is welcomed by his people.
Also about the same time, the Romulans show up. It is a tearful reunion after so many decades of absence.
The Pah Wraiths are discovered as well; except for having a different essence color when about inhabit a corporeal lifeform (that one is red and the other blue is really convenient for us to tell them apart), they turn out to have exactly the same values as the Prophets, so they merge.
Even Eddington is an amiable character who has no issues with anyone, and who most definitely doesn't drone on and on about his homegrown tomatoes.
The series ends with a massive party/reunion where everyone who ever appeared on the series comes together to celebrate their friendship.