When My Little Pony Friendship is Magic reaches season number six next year (2016), what should we expect?

The top of the list of course HAS to be the new baby of Princess Cadance and Shining Armor. No question about that!!!

But what else?

The return of a major MLP villain. Likely King Sombra or Lord Tirek or Queen Chrysalis (with her horde of Changelings of course).

The Cutie Mark Crusaders will try to help other foals gain their cutie marks. For example, Pipsqueak, Rumble, and Button Mash. The CMCs will perhaps gain some male members.

The debut of Fluttershy's brother. I am going way out on a limb by suggesting that in Cloudsdale Fluttershy's parents are divorcing (see below), and a serious dispute over the custody of Fluttershy's brother ends up with Fluttershy becoming the legal guardian of her own brother, who moves to Ponyville. The relationship between Fluttershy and her brother are somewhat strained (he regards his older sister as too much of an animal lover). However, "Flutterbro" does bond with the draconequus Discord, as well as certain other Ponies, such as Big MacIntosh, Dr. Hooves, and Derpy. He is attracted to Scootaloo or Apple Bloom as a potential girlfriend.

Starlight Glimmer tries to mend fences with Sunburst.

Wind Rider (my wild guess) turns out to be Fluttershy's father, and he is divorcing from his wife (Fluttershy's mother) because of the events in Rarity Investigates! where Wind Rider is expelled from The Wonderbolts because Fluttershy's mother now views her soon-to-be ex-husband as a bad role model for her son. Wind Rider is estranged from Fluttershy (his daughter) because he views her as too much of an animal lover.

Fluttershy's mother (my guess) is talented in communicating with and controlling birds. My guess her name is Ladybird. Wind Rider flees with their son to Baltimare while they are in the process of divorcing, and Ladybird follows them accompanied by a swarm of birds.

Twilight Sparkle and Fluttershy broker a compromise on which she becomes the legal guardian of her kid brother and Wind Rider and Ladybird retain the right to visit their son.

More possible stuff for MLP season 6?

How about a female unicorn (Twilight Nemo) who is the captain of an airship (the Nautilus) that includes other ponies (mainly Earth ponies) and even Griffons and Diamond Dogs as crew members. Nemo is the first cousin of Twilight Sparkle and Shining Armor, and an old acquaintance of Princess Cadance. She originally attended the School for Gifted Unicorns, but she dropped out of school because she thought Canterlot life was too boring.

Could Rainbow Dash have a sister? If she's older than Dash, perhaps she originally joined the Royal guards but later dropped out or was expelled due to offending a member of the Equestrian royal family (Prince Blueblood?). If Dash is older than her sister, then maybe RD's sister comes to Ponyville to attend the Ponyville Schoolhouse as an exchange student from Cloudsdale.

Could there be a new griffon character introduced in the series? Perhaps the kid brother of Gilda, who perhaps comes to Ponyville from Griffonstone as an exchange student?