To be clear, this was written after Maud Pie came on. Also, this isn't about things like "Pony Jigsaw putting Diamond Tiara in a saw trap", "King Sombra returning", "ponies calling Minuette/Colgate by her fan name", or "Rarity being killed off", this is about things that sound like they could happen in the show, and are probably expected or hoped for by many, but most likely won't happen for reasons I'll describe below.
5.) Queen Chrysalis returning
I'm sure a lot of you would like to see the "best villain" return, but if you do, read the comics, you can view them as canon if you wish. Comics aside, Chrysalis took a fall over a mountain, seemingly unable to use her wings, and she's more like a Disney villain than the comical Team Rocket, and for those reasons I do not think Meghan intended her to get back up, but she does not want to admit it either to avoid disappointing the fans who want her to stay breathing or else because she respects those who view the comics as canon and knows of the Chrysalis arc.
As to the actual notion of a Chrysalis return, if it was about defeating her it'd be repetitive, and if it was about reforming her a.) they already played that card with Discord, and b.) If people hated Discord's redemption when he was loved for being a fun guy to have around, imagine the uproar if in canon they reformed his only competitor who, unlike him, was loved for being surprisingly dark and having epic battles revolving around her? Sure, plenty of fanfics have depicted redemption for her and even made her sympathetic, but look what happened the last time they based something off of fan works.
I've written a few blogs all about Chrysalis and made some comments so I just covered the basic points here. (queenchrysalis)
4.) Rainbow Dash having her own song
We'd all like to see that, as of Apple Family Reunion she's the only Mane 6 to not have her own song, closest she comes is sort of a duet with Fluttershy in May the Best Pet Win. However, as far as I remember her last singing role was in Bats!, and in the following episode Rarity Takes Manehattan she's tired of "ponies bursting into song in random places". There is speculation it will happen in Testing, Testing, 1, 2, 3, but as they haven't confirmed this as an episode with a song in it it's unlikely.
(edit: posted before the Mane 6's song at the end of Season 4. Also, I'm referrring to the pony, since her human counterpart does have a solo "Awesome As I Wanna Be")
3.) Lightning Dust returning for redemption
Some of us love Lightning Dust as much as Trixie, and kind of have a love/hate thing going for her. As she does not seem pure evil, and some don't even count her as a villain, how many of us would love to see Lightning Dust return and turn good like Trixie did in Magic Duel? (imitating Fancypants) I know I would! (regular voice) But sadly, it won't happen. Why? Because they intended a redemption in Wonderbolts Academy. They intended her to realize how reckless she was after almost killing the other Mane 5 with her tornado. Instead they had her show disregard for the lives of the ponies she almost killed and last we saw of her her status as team leader was taken away much to her disappointment. So if they didn't redeem her there when they had initially intended it, they won't redeem her ever.
2.) A new villain of a two-parter on the same level as Chrysalis, Sombra, Demon Sunset Shimmer, and Nightmare Moon
Now I've said it a million times so I'll just skim the key points: They could have done a lot better than black vines for the "villain" of Princess Twilight Sparkle, and while they were menacing, got a spectacular death scene, and did a nice twist with the facehuggers, they were created by Discord before he was turned to stone the first time but were suppressed by the Tree of Harmony until now, after a thousand years, the tree's magic chose this moment to deactivate for no apparent reason? Was that the best they could do? No new villain to create the vines in the present? I'd say they were running out of ideas if it wasn't for some of the good one-shot villains this season like The Mane-iac and the chimera, but maybe they're unable to come up with one whose story can last two episodes, or else just lost confidence after the reception to King Sombra (which was only for lack of screentime and dialog, if he had more screentime they'd love him as much as Chrysalis and I like him almost as much)
Also, I didn't count Starlight coz she's not quite on their level, a regular old unicorn even though she's even more powerful than Twilight, and while she did have an impact, it was the other villains she gave power to
1.) The Cutie Mark Crusaders getting their cutie marks
We know what their special talents are and they're right in front of them, but they just don't realize it. Also Sweetie Belle's stage fright prevents her from atleast accepting that singing is her special talent, and Scootaloo doesn't get the whole "finding who you are" part of it. The only one who has any realistic chance of getting her cutie mark is Apple Bloom but the Cutie Mark Crusaders will likely come bundled together.
Not every pony is destined to get a cutie mark. Most of them do but Sapphire Shores is a blank flank, and so was King Sombra when he died. Also, if Rainbow Dash hadn't done that one Sonic Rainboom as a filly, none of the Mane 6 would have gotten their cutie marks. Which makes for a big "What if" story (edit: which will be explored in The Cutie Remark with Starlight Glimmer, possibly leading to returns by Chrysalis, Sombra, and Tirek, and definitely leading to Starlight's redemption as has already been revealed)
Another thing: Fear of change. It's human nature, but when Twilight became an alicorn, over half the fandom raged. That's dead now, and I know most of you probably want them to get their cutie marks on account of "looking for their cutie marks is getting kind of stale", but they probably want to avoid it now for fear that the audience will react as badly to it as they initially did to Alicorn Twilight.
So, what do you think of the list? Comments would be greatly appreciated but please, no flaming, especially in regards to Chrysalis and the "out of villains" theory which I know I've talked about a lot. Also I would like to see everything on this list, except a Chrysalis return becuase I want her to be dead from her fall, that would be the perfect end for her