On what episodes would need to be there to fit with joining the first 6 to the last 10 you would probably need these 9 at the least:
1.You Are Cordially Invited - The fact that Worf and Jadzia were married is a big part of the angst of Worf and Erzi.
2.Waltz - Shows why Dukat is off running around being naughty.
3.Change of Heart - Explains why Dax isn't on the Defiant in Tears.
4.Inquisition - Introduces S31.
5.In the Pale Moonlight - Romulans join up.
6.Tears of the Prophets - Dax dies.
7.Image in the Sand - Given Ezri is in the final epis, you need to introduce her.
8.Shadows and Symbols - Wraps up things from the previous ep.
9.Inter Arma Enim Silent Leges - Referenced in the final episodes.
That leaves one episode to play around with, which would cut out It's Only a Paper Moon, though you could still get away with The Siege of AR-558 as it wouldn't be the first time DS9 just moved on from something that happened in an episode without any explanation or call back.
In the end it would have made the entire thing feel rushed. You do lose a lot of character moments for various people and depend on the final ep picked there would be no more MU, Ferengi, Jack Pack stuff (though some would consider that good). Vic would be a big loser and it would make the addition of Ezri worse than it already was. In the end combining the final two seasons into one is possible, storywise, but imo it would make the show worse.
