With the new season starting soon, here's the list of characters that should get moar development/episodes.

Finn: In a dramatic turn of events

Jake: We really don't see much of his past or anything

Flame Princess: DUH? She needs moar episodes

Peppermint Butler: He's so creepers

Lady Rainicorn: Is pregnant

Ice King: See Marceline

Marceline: See Ice King

LSP: She was in like, 2 episodes in season 4. UNACCEPTABLE

Beemo: We love Beemo. You better say you do ಠ_ಠ

Hunson Abadeer: Part of Marceline's past

Lich: Needs a personality

Prismo: Needs a girlfriend

Aaaaaaaaaaaaaaaaand Billy: Because I said so