I've noticed that one of the problems with a show like DS9 increasingly relying on an arc is that viewers eventually are only interested in the arc. The show becomes are victim of its own success in that respect. For DS9 that has meant that many fine episodes that were broadcast towards the end of its run get criticised and sidelined simply for not being arc episodes.
However, DS9 was never Babylon 5. For the first five years of DS9 the so called arc was one of its weakest aspects. With too few exceptions (eg, Jem Hadar, Improbable Cause), the early arc episodes ranged from mediocre (eg, Apocalypse Rising, The Adversary, Way of the Warrior (there, I said it!)) to downright terrible (eg, Broken Link, The Search Part 2). The writers would be foolish then to rely on the arc for an entire season. And when you get terrible episodes like Sons and Daughters and Extreme Measures at times when the show couldn't get more arc-based, I start to think they had already pushed their luck too far as it was.
I thought season 7 overall was pretty strong and never quite understood many of the criticisms directed at it. Yes, there were a few rough patches, but when was DS9 ever perfect? Episodes like Take Me Out to the Holosuite, Chimera, Badda-Bing, Badda-Bang, Inter Arma Enim Silent Leges, Once More Unto the Breach and It's Only a Paper Moon showed there was more to DS9 in its final season than the Dominion War. And that's how I always liked it.
And I think Ezri ended up being more compelling and memorable as a character than Jadzia ever was (and I liked Jadzia). She was asked to carry a couple of awful episodes when she was first introduced and that understandably soured her impression in the eyes of many fans. But she ended up being one of the best things about season 7 in my opinion.