Every season they try to figure out a way to make the show bigger and better, but have trouble figuring out a way to top themselves. They totally figured it out for season 5 already.
Princess Luna has a nightmare, episode based on that most likely?
Entire solo song for Rainbow Dash
This season has the 100th episode, which is sufficiently awesome and focused on characters that have been on the show for a while, but mainly in the background. Coco Pommel returns for one!
Maud Pie returns. Entire Pie family episode.
Twilight really misses her library, and their is an entire episode about it.
Q/A from Comic Con
Will Twilight's Library ever come back?
Will Flutterbat Come back?
Mike Vogel wants her back!
Will the CMC Ever get their marks?
You'll have to wait and see!
Will Chrysalis be in season 5?
In spirit, and maybe
Why hasn't the concept of Applejack's parents been approached?
It is an important lesson for kids that may happen, but they have some trepidation on how carefully they would need to handle something like that, and they havent figured out a good way to deal with it.
Will any of the characters in the official comics sneak into the series?
It's certainly a thing they would consider since the characters already exist. They try to keep the universe of pony connected.
Will we be seeing seaponies?
Anything is possible!
Will anymore classic g1 ponies return?
Will Spike sing in Season 5?
Jayson thinks she should have an epic rap battle with Pinkie Pie.
Cathy wants to do one.
Is Twilight going to have any relationships?
Possible wars were going to happen up in here at that one! Twilight dates ALL THE PONIES.
Little kid asks if DJ Pon-3 would be in the foreground.
Will Starswirl Appear in season 5?
He's always there... watching... waiting... Just for the right moment.