I think what really worked for this episode that made it stand out above others (besides the fact I'm cuckoo for Frankie puffs
) is the fact it managed to create a unique, different kind of story for a minor character and make it interesting and funny. I mean when you think about it, this is a really different episode.
The focus comes on a side character, the plot is exceedingly more adult and teen like (dating, falling in love, sexuality etc.) and they managed to make it work in a kids environment with child like characters. I'm still applauding the fact the creators decided to make Bloo and Mac fall in love with Frankie, kids drooling at an older parental type figure is not something I see too often.
Usually "puppy love" is ignored upon and the children characters view lovey dovey stuff as "ick" in their words, or too confusing for them to understand. Here, its used quite well and it actually shows up AGAIN! Solidifying the fact it wasn't a one time gag. Plus, its nice to actually see other people in Frankie's life other then her grand mother.
Outside of Kathy and Frankie's infamous mystery parents, we don't know a damn thing of who exists in Frankie's history or even how she met Dylan. I know that's kind of useless information considering Dylan is a tool, but I am curious as to wonder how those two met.