Sea Ponies: Remember them from G1? If we had to endure the Abominations from G3, then the Seaponies are not as far-fetched. Yeah, I'm NOT a fan of the Breezies... but I love the Sea Ponies! I know they have appeared on a book, but that's a book and not the cartoon.
An Episode With The Doctor: Well, this was to be expected. We've had a few cameos of The Doctor and a Pony whose name happens to be Rose(luck). I want a bit more. I want The Doctor to have a speaking Role... While yes, it would be insanely awesome to get A DOCTOR to voice him. At this stage I'll take a guy with a Hammy Over the top fake British Accent at this stage of the game.
Stick him with Twilight so we can have the classic Doctor Who conversation:
DH: I'm The Doctor!
TS: Doctor what?
DH: Just The Doctor
TS: Doctor of what?
DH: THE Doctor
Or a scene where Discord shows up carrying a Plunger and an Egg Beater and Doctor Hooves freaks out. (we could also use Statue Discord coming to life when he isn't looking.
Sadly, this is very unlikely to happen unless Hasbro, DHX and the teams involved with FIM get an OK from the TARDIS BLUE guys across the pond...
The Cutie Mark Crusaders getting their Cutie Marks: We've gone through 4 seasons and their flanks are really bare. It would be sad to see the show end BEFORE the CMC get their Cutie Marks.
Sure some might say that them getting their Cutie Marks would End their usefulness as Characters...
To them I say: *shudder* Look at Twilight Sparkle. She is still Our Nerdy and Socially Awkward Twily... but She now has Princess Wings... Isn't it Amaaaaaaaaziiiiiiiiing!? Sure they wouldn't be the Cutie Mark Crusaders anymore, but their team could get a new name... The Filly 3?
Lord Smooze: Yes, the Lord Title comes from the MLP FIM Parody MLP friendship is Witchcraft... That even the FIM Team has acknowledged in Equestria Girls... Or a freaky coincidence... Having Smooze in the show could help the FiW team to finally have Smooze!
The Return of past nuisances/villains: Talking about folks like Iron Will, diamond Dogs, Gilda, or Sombra... Especially Sombra since his single appearance was so pathetic that he needs to redeem himself. Also, I want more excuses for Twilight to go Super Saiyajin!!
Now on the OTHER Hand, here's 4 things that I DO NOT WANT to see in Season 5
Multiple Rarity-centric episodes: I don't Like Rarity... I think I have established that already. Almost all of Rarity's "Friendship lessons" can be summarized to: STOP BEING A SELFISH
I'm not saying NO RARITY EPISODES... Just keep them to a minimum... Because even Sweetie Belle-centric Episodes get turned into Rarity Episodes. Although, I wouldn't mind more Rarity AND Applejack Episodes...
Humans: Sorry Megan and Siblings... You should remain in G1 forever... I already got my fill of MLP Humans in Equestria Girls.
CMC-centric Episodes (aside the one they get their cutie marks): Before I get attacked by mobs of CMC fans. I mean CMC-Centric Episodes as in all three Members of the CMC are doing stupid stuff that will NOT GET THEM Their Cutie Marks. This is NOT the same as saying no to episodes with Apple Bloom, Scootaloo and Sweetie Belle. It's just when they are in CMC-Mode, the three of them become 1 annoying character with 3 voices.
Obvious Marketing Episodes: While Royal Wedding, and Rainbow Power Episodes were good, the Crystal Empire sucked ass (except the Fastball Special) I can say the same thing about them Breezies (Doctor cameo aside) While Sea Ponies would count as an Obvious Marketing episode, it's the Sea Ponies, a staple from Generation 1!