I think I agree with you on Past Tense. I enjoy the episodes - they're well done and effective enough. They don't quite have the clout as some of the other two-parters DS9 did though. (I'm thinking The Maquistwo-parter; Improbable Cause/The Die is Cast; Homefront/Paradise Lost; and In Purgatory's Shadow/By Inferno's Light.)
It was a random use of time travel, but I like how it just sort of happened. And I also enjoyed Kira and O'Brien beaming down to the different time zones in part two.
I also really like Sisko in these episodes. It's season three where Sisko has been dealt with in a more interesting way than what we had before, and Past Tense gives him another chance to operate outside the box. It was good development for him.