The title is what I typed into the talk page for the page "The Duke". I mean the episode, not the character.
Princess Wintergreen seems like a nice new character to me. If she gets popular enough [which I think she would more likely not], maybe we can somehow direct her in the same path as Fionna and Cake.
Fionna and Cake, as you may know, are the gender-swapped versions of Finn and Jake. Their popularity led to more gender-swapped characters and the episode "Adventure Time With Fionna And Cake". So, what does Princess Wintergreen lead to? Characters that are like brothers and sisters to Finn and Jake's cast, but not gender-swapped like Fionna and Cake's cast.
Still, she may not get very popular. For now, she's just Princess Bubblegum for the majority of the episode "The Duke". We'll just have to wait and see to know whether or not she stays that way.