What is really hokey about "Dynamic Duets" is the superhero theme. For viewers, it's great fun to see the characters in costumes, and the editing of the episode in the campy hero style, a la Adam West's version of Batman, is amusing. However, it would be extremely rare for a single high school student to have the guts to wear a cape and tights to school, let alone a whole group of them. It feels like a cheap gimmick, rather than a well developed arc. Not to mention, it will surely be shown only in this one installment, with no mention in episodes before or after it, making it completely ridiculous.
Luckily, "Dynamic Duets" is saved by the character development. First, there's Blaine (Darren Criss). The new captain of the Warblers, Hunter Clarington (Nolan Gerard Funk, Warehouse 13), tries to entice Blaine back into the fold with a blazer and a song, "Dark Side." Somehow, Blaine is tempted, even though it's one of the least memorable numbers the Warblers have ever performed, and his former arch-nemesis, Sebastian (Grant Gustin), is still a part of the group, albeit, less evil now.
Music aside, the real reason Blaine considers leaving is because he is down on himself. After cheating on Kurt (Chris Colfer), and never really allowing himself to feel accepted by the others, it makes sense for him to leave. It's part punishment, to help ease his guilt, and part melancholy. Thank goodness Sam (Chord Overstreet) is paying attention, though, because as soon as he steps in, Blaine not only begins to feel better, thanks in part to hokey good deeds that come out of nowhere, but it also leads to a terrific duet of "Heroes." Blaine is finally a full-fledged member of the ensemble in this episode, in a way he hasn't been all season, in the eyes of both viewers and the character himself.
It would be a crying shame to lose Blaine. He did a bad thing, but at the time, Kurt was driving him away. Plus, he has punished himself enough. At some point, Blaine has to begin to forgive. I think a large part of his alienation at McKinley this season stems from his negative view of himself because of the cheating, and it's nice to see him start to heal. Blaine is not a bad guy, and hopefully he will get a reunion with Kurt soon enough.
Speaking of Kurt, "Dynamic Duets" stays away from the New York setting entirely. It's the second episode this season so far to do so, and I have to admit, this is really working for Glee. I love seeing Rachel and Kurt's adventures in the Big Apple, but these scenes feel tonally like a completely different show.