It's a weird show. The stupid Universe story was silly and should go away, as DS9 just wasn't really like TNG or VOY in that way. Well, when it was being good. We have been revisiting seasons one and two after all!
I guess I give the episode a bit more credit (not much, mind - 2-2.5 stars?) with the Arjin storyline, as I found it relatively interesting. Jadzia keeps knocking him back and taking him down a peg, as she struggles with how Curzon rejected her from the Initiate Program. It was a decent enough hook, but I think that in the end, it just didn't play out properly.
And shoving a sci-fi gimmick into the mix didn't help the problem, it just made it larger.
I always loved the Trill though. I enjoyed the idea of the symbiant continuing to live after the host died, as their memories would go on and be re-lived in a way not possible with us. Relationships with friends and other races could potentially for a long while, and I just feel that a race wielding this much presence could have had more of a role in the proceedings somehow.
I find it amusing how having a symbiant inside a host is a bit gross and parasitic in nature, yet their is a great importance and honour in having one.