Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Preachy
Aristophanes appears just as interested in bringing us over to his views as his character Socrates. With the Chorus weighing in early and often on topics ranging from Athenian politics to the characters' busted moral compasses, we get a clear sense of what constitutes right and wrong in the play's universe.
For example, the Chorus literally lectures the audience about their political choices during the parabasis, taking after them for having elected a dude named Cleon (whom Aristophanes had criticized in his play Knights via the character of Paphlagon):
"Spectators and critics, give an ear to what I say. / We've a gripe against you, and we'll lodge it openly. / Of all the gods we do the most good for this city, / but we're the only gods that get no sacrifices, / no libations, though we look out for you. Whenever / you marshal a stupid expedition, we rain and thunder. / When you went to vote for the god-hated tanner Paphlagon, / in the election for generals, we knitted our brows together / and made a lot of noise with lightning and thunderbolts, / and the moon eclipsed herself from orbit, and the Sun / pulled his blazing wick right back into his lamp and refused to shine on you if you elected Cleon." (575-586)
That's some pretty intense preachiness, if you ask us—especially since it's directed right at the audience. Of course, the Chorus also goes after the characters. For example, when Strepsiades finally realizes the error of his ways and asks why the Chorus didn't warn him away from Socrates, the Chorus Leader doesn't refrain from telling him he should have known better, saying,
"No, you're responsible for doing it to yourself: / you took the twisting road that leads toward evil." (1454-1455)
You tell him, Chorus Leader. That doesn't sound vindictive at all.
So, you get the point: the play doesn't refrain from telling pretty much everyone what s/he should be doing.