Fiddlesticks thoughts: scarecrow teleport ability, basic attack animation, and fiddlesticks voice
Things that would be most totally epic:
pseudo-teleportation: let fiddlesticks create scarecrows around the map, maybe randomly anywhere, maybe only in brush, maybe "he" has to plant them, that give vision and /maybe/ a mild status effect such as 10% slow away from them or reduced mr when fiddlesticks is nearby at higher levels. Let him use crowstorm to jump into them by having the demon in his chest body hop into them. Maybe he doesn't use crowstorm, but has a percent chance to make the jump. Scarecrow in the middle of the road, will it come to life?
basic attack animation: can this involve the scythe for range and the claw for melee? I think seeing the demon pop out constantly kind of makes the scarecrow suit seem pointless, but that's my personal taste. I want to see his gruesome weapons put to use.
voice: Being an entity confined to a simulacrum, a demon in a scarecrow built to house a "soul", couldn't there be victims inside fiddlesticks suit? What if in addition to the demon voice there where the distorted, terrified voices of the champions he kills, chosen randomly each time they play, as well as voices from past victims? What if the demon had no voice and all fiddlesticks ever uttered where pleading screams? I would suggest that such voices should emanate from the aforementioned scarecrows planted around the map. Terror everywhere.