Dork Age: Gyu! is seen as this due to the change in the show's formula as well as Junichi Sato leaving the series.
Fan Preferred Pairing: Rein/Eclipse was, at least, initially more popular than the Official Couple Fine/Eclipse. In a popularity poll done by the Japanese fan community, Rein/Eclipse topped the list. Even the artist of the manga adaptation, Mayuki Anan, seems to lean towards this pairing as well since this pairing got the most Ship Tease despite that all pairings were left ambiguous in the end.
Les Yay: Sure, Altezza got paired with Auler, but there was plenty of this between her and Sophie.
Memetic Mutation: When Rein got pissed with Altezza in episode 10 of the first series, she yells, "What was that?" ("Nani yo") to which some Japanese users phonetically transcribed it as "Haniho" and ran with it.
They Wasted a Perfectly Good Character: Several princes and princesses from each of the kingdoms only show up for one episode or less. Prince Solo from the Seed Kingdom comes to mind: he was only briefly introduced in one episode of the first series. He was then given a A Day in the Limelight in the second season before being shoved into the background altogether again.
Toy Ship: Milky and Nalro got some Ship Tease and both of them don't even know how to talk yet! Nalro hasn't even learned how to walk!