Any thoughts about Don Giovanni generally? Or what the effect of opera overtures that quote the final scenes has on the audience? DG’s overture is shocking, as is the end, but when I noticed this device in Figaro I was unmoved.
By "device" I guess you mean the opening D major/minor tutti chords in Figaro/Don Giovanni? (And the Figaro overture leaves you unmoved because its material is self-contained?) The most important difference between these two overtures is that the Giovanni overture is contingent on the drama to follow -- the D major chord fades away, and then, after a sort of musical caesura, modulates into the buffo F major of the Intro. It's dramatically incomplete.
But Don Giovanni is interesting because of its characters. The crisis between man and God, and the problem of man in relation to God, doesn't interest me so much as what Elvira is thinking when Leporello is unrolling the infinite scroll, where every name becomes a number (painstakingly counted up and fussed over): after her first, antique & seria aria, we know she's reading the dramma giocoso as a somewhat stuffed-up baroque tragedy, and we also know that as she listens to Leporello's mock-song, which is absurd and almost merry, she realizes that she is one of those numbers.
We know this because of Mozart's music -- if someone like Rossini scored this libretto, it's not hard to guess how he'd do it. A sort of social farce, with a group reconciliation at the end, and the offending people pushed out or converted. But in Mozart's opera, there's no reconciliation (aside from Zerlina's aria in the second act, where she comforts Masetto after he's been assaulted and beaten to a pulp), and there's no social comedy -- the chorus and ensembles in the first finale serve as the backdrop to the Don's attempted rape, and the ensembles in the second act either deal with masks/mistaken identity/seductions or the somewhat lame moral at the end. (Aside: at the first Vienna performance of the work, a few numbers had to be cut because of time, & Mozart took out the epilogue. But so that the audience would know the other characters knew about the Don's fate, he asked them to run out onstage together, after the Don was dragged down to Hell, and scream in D major. When it was time, they ran out onto the stage, as instructed -- and just screamed.) And at the end of the opera, Donna Anna separates from Don Ottavio for a year, the madwoman Elvira becomes a nun, Leporello heads out for a drink (and to find a new master) -- and Masetto & Zerlina begin their married life. The dissoluto is punished, and society is dissolved with him (and because of him). Don Giovanni is a tragedy of the disintegration of human society -- and the eponymous character himself is more or less a nonentity (with a few short arias) who leaves broken marriages, violated women, jealous men and misery behind him, wherever he goes.
So those are a few thoughts, unripe. I'm not really in the mood to talk Don Giovanni, overture or opera -- but you asked.