Didn't R/S introduce the swarm feature that predates the horde battles or am I misremembering?

Well, firstly, it was actually introduced in Gen II.

Secondly, swarms and hordes are not even close to the same thing.
Swarms (or, more formally, Pokemon outbreaks,) are temporary outbreaks of a species of Pokemon (usually relatively rare in that game) in an area where they are normally not found.
Horde battles are battles against a GROUP of Pokemon, that has nothing to do with being "temporarily" in a certain are.

So anyway, back to the topic of this thread, I think Super Training, or an alternative to it, will definitely return. It's a too important aspect of competitive team building. When I say "alternative", I mean that it's possible they could replace it with something else, even call it a different name, but it will still have to do with training EVs.

It honestly doesn't matter to me if hordes return or not, but going by what has been done in previous remakes, it makes sense that they would return. IIRC, there were double battles in FRLG and HGSS although there weren't in the original. And, there's nothing really PREVENTING them to remove hordes.
Maybe they could fuse "hordes" and "swarms" together? Other than the words sounding similar to each other, I think it actually could be a good idea, cuz then you'll know WHICH Pokemon is in the swarm. I mean, I must have past dozens of swarm-filled routes in Platinum without knowing it. By making the swarm Pokemon have different battles, it would be easy to know, without having to contact anything, which Pokemon is in a swarm.

The return of Pokemon amie seems likely, considering affection. But they could introduce other ways to increase affection as well. Then there's also Sylveon... (which has been discussed to great depth in another thread...)
IF Pokemon Amie does return, I hope they can add more to it to make it better. What @Piplup; said is a good idea: PokeBlocks should replace Pokepuffs. It makes sense cuz OUTSIDE of Amie, Pokepuffs have no use, i.e. they are as disposable as Pokemon Amie itself. BUT, PokeBlocks DO have a use in contests... (Although Poffins could replace them, but that's another topic....)