I think Endgame is the best finale relative to its series. Voyager was badly written, the characters were one dimensional (at best), it had lots of stuff in it to make stupid people think it was being smart, and it relied pretty much totally on the leavings of TNG, especially the Borg. I think Endgame fulfilled all those criteria, and as bad as it was when compared to other trek, it was probably more enjoyable than most Voyager. I think for the people who enjoyed Voyager it was probably a perfect finale.
WYLB, on the other hand, was overcrowded and not nearly as well written as most other ds9. I thought the end of the Dominion War was okay, but the battles were nothing I hadnt seen before, and I frankly became pretty bored while I was watching them. Then everyone got back and the whole pah'thetics thing kicked off, Sisko went down to Bajor, and fell in the firepit. YAWN. The two major ds9 arcs are both bought to an underwhelming climax, within the same damn episode! Then on top of that youve got the stuff about Odo leaving, Garak leaving, O'Brien leaving, Sisko coming back to talk to Kasidy. It was all just too much, all those things carried too much weight for that one show and the writers didnt have enough time to concentrate on all of it. Thats why I think an extra episode would have been good, even if they had to do the stupid fire caves thing with Sisko, they could then have spent the next episode with everyone leaving the station, really give it some emotional depth, instead of a damn set of montages, the laziest plot device in the history of time. You could also have seen more of Jake without his father, and then Sisko could have come back at the end of that episode.