"Past Tense" was incredibly preachy. The high point of the episode's preachiness is where Bashir goes "how did we ever let it get this bad?". I almost expected him to stare into the camera and shed a single tear or something. Oh and Siddig's acting was beyond atrocious in that episode, it made my skin crawl. The message wasn't subtle, it was just so blatant and heavy handed.
Some of it was OK. I enjoyed some of it, I'd probably give it a 5 or 6 overall.
To each his/her own. I personally think that Past Tense is extremely underrated. It's among my favorite 5 or 10 episodes of the series.