F***, "deceptive cadence" is one of those puns that's so good I wish I thought of it first. Oh well. (I don't think this is an intentional joke on the composer's part by the way, deceptive cadences are common in music and he didn't even use them during the villain's theme.)
I didn't really like this episode much, the episodes that are all disney movie plot and song numbers with flavor-of-the-week villains don't really do it for me (except Discord who is great), it just isn't what I like about FiM. I think this episode would've been funnier if the plot was "Twilight ruins the wedding after becoming paranoid about a completely imagined evil plot against her brother", but that would've been a completely different episode. Villain was lame and didn't really introduce any real tension to the plot despite their desperate attempts to introduce real tension to the plot, but at least she did have a cool design.
Not a really bad episode, just not my thing. Like I said, I think if you take the villain out but leave Twilight's neuroticism in I would've been more entertained.