Glee already went down this path, having students lusting after others who don't share their sexual preference, in the early days of the show, when Kurt had a thing for Finn (Cory Monteith). It doesn't need revisited.
One could make the argument that these characters are in high school, and their recent actions are reminiscence of how teenagers actually behave. The problem is, Glee is not consistent with that behavior, so when a plot like this comes around, it feels uneven, and does not make for the best episode.
The best part of the entire "Sadie Hawkins" plot is that it returns Lauren Zizes (Ashley Fink) to the show! Her role is brief, and she should have already graduated, I think. She also acts completely out of character from what we've seen of her before, and I don't buy that her man messed her up this much. It just doesn't feel like the woman that character had grown into when we last saw her, even if that's how her character was originally introduced. But I've missed Zizes (and Fink) so much that I am willing to overlook the writing flaws if they will only make her a recurring player again (or better yet, a series regular), and then effort can be spent on taking her back to her former glory.
Why is Sugar (Vanessa Lengies) in the Too Young to Be Bitter club? She can be annoying (to some, I actually like her), but she's hot, and looks trump personality in a high school setting. Someone would have wanted to go to the dance with her.
Marley (Melissa Benoist) decides to fully go after Jake (Jacob Artist) this week. I feel like their back and forth isn't progressing, but they're good together, and I Marley and the rest of the girls, including Unique (Alex Newell), sing quite an enjoyable "Tell Him." I hope this isn't one of those will-they-or-won't-they stories that is stretched out over three years, even though that's probably exactly what it is.