There’s three characters I really want to see something done with in S4.
Fluttershy, now that she doesn’t have to be her Element constantly, should be something more than a doormat. I don’t know, just don’t make her learn the same lesson again.
Applejack needs characterization that isn’t about the farm or family very badly. It’s all she is at this point, and its getting a little weird.
With Spike, I just want them to be sympathetic to his character instead of using him for physical comedy constantly. I’ve talked before about how using him for that makes the ponies look terrible, but it’s true. Have him save the day again and be triumphant about it, have him get closer with Twilight and Rarity (in different ways), or go over his backstory. They’ve tackled bigger things than a slightly depressing and dark story of a dragon’s origin.