User blog comment:Mattalamode/A Second Opinion: The Detective/@comment-9300845-20170617030802/@comment-31194372-20170619051442

Part of Penny's issue is that she was written directly as Gumball's romantic interest, no other strings attached. Compare that to Carrie, who was already a fully-formed, distinct character prior to her relationship with Darwin. There's just a lot less room to really go beyond the confines the show already set up for Penny, and she generally gets less episodes as a result. She's not bad; she just lacks a general capacity to do anything further.

I'm hoping that Carrie, if not carrying a lot of episodes, at least makes more solid appearances where she does more than serve as a cameo. Mostly, I'm just a bit surprised the show didn't want to jump on the Carrie bandwagon any sooner in the same way that "The Bros" sought to follow up on the effect of "The Shell," especially since they've been setting up her and Darwin's relationship since Season 2.

As for Nicole... I have no clue why she hasn't made so much as a simple, one-line appearance in most recent episodes. It's just odd that she's never even around their house anymore, whereas Richard is practically all-seeing at this point.