Addressing each of your points one by one:
- Ironically the first thing I want to see is a more streamlined 3rd person camera angle that isn't at all like Lumiose City whiplash cam, should they make Slateport or Lilycove a monstrous city, or just try to add some neat viewing effects.
Unlikely. The cities will remain identical, going by all other remakes.
- I want to see a return of the Battle Frontier. I never played Emerald, but looking at what it did for competitive battling (which wasn't so much a thing as it is today mind you) was revolutionary and could be expanded on so many fronts. For example, they can leave the Safari Zone in-game be and put the friend safari at the Battle Frontier (Basically, Kiloude City is the Kalos BF)
Not so sure about Friend Safari, but I'd bank on the other stuff being true.
- I want to see Trainer Customization make a return, instead of having to appear as an Ace Trainer or something in competitive battles. Plus, Dress up is fun.
Very likely.
- I want to see more encounters with Wally. This doesn't mean Battles, but I would love to see him have a side story that is actually told on screen.
Very unlikely. If we're lucky, we MIGHT have him as a once per day battle in the post-game.
- I would like the ability to get starters from Generations 2 and 4, like Kalos.
Nothing new here. You could already do that in Emerald.
- I would like to see Secret Bases be incorperated with Streetpass mechanics instead of being able to locate them after your friend tells you where it is, as well as functionality with the PSS.
They'd be crazy not to do this.
- I would like the opportunity to catch either Deoxys or Jirachi in-game, as opposed to both being event Pokemon.
There is no way that this would happen. Be serious.
- I would love to see Swampert and Sceptile get Mega-Evolution love, if that's going to be a thing in Hoenn this time around.
I'd put money on one of them getting it, but only as an event. Or maybe Sceptile for Ruby and Swampert for Saphire? Maybe 'Z' would have the third one.
- I would love some post game story that is unique to this remake only.
Could happen. We had the whole Sevii Islands arc in FR/LG after all, plus all those extra routes and Kyogre/Groudon and Govanni in HG/SS.
- I would love to rebattle trainers and gym leaders using Match Call on the PokeNav.
Again, nothing new here. Emerald already did this.
- I would love to see new Mega Evolutions, mostly for Pokemon that are relavent to the story, such as Camerupt and Sharpedo, or Mightyena, along with Pokemon that are not usually used.
I'd say pretty likely.
- I would love the ability to use field moves such as Rock Climb and Waterfall to explore new areas.
Rock Climb won't be a thing. Waterfall is already used to explore areas.
Also Bibarel-you only JUST found that? When there were hundreds of thousands watching the live stream? =D