Oh come on. The battle frontier was one of the best things in Pokemon games. There's no reason it shouldn't be in these remakes.

It would probably come out later as an update. Even if they said that the project began on 2012, I wouldn't be surprise that the development/coding/whatever of the game, didn't began till a bit of time before the big reveal, so it wouldn't be surprising that Nintendo rush them to get the game out by November, so they had to leave some things out to add them later via updates, including the Battle Frontier.

Well that or there are some requierements to do in the game, and it gets build as you do it, something like defeat the E4, a certain number of times or something, though I doubt a Delta Emerald, specially now that we got the Delta Episode thing.

To play the Battle Frontier. It seems we may have to for an Emerald Remake or hopefully (doubt it) free DLC.

Despite the fact that I really like pokemon it is one of the most milked franchises out there.
Just think about it, they have released a ton of games that barely evolve when it comes to singleplayer. (I have no complaints about the competitive), and if I eventually buy ORAS I will have bought the same game three times. 3 TIMES ! The same game! I first bought Ruby, then emerald, and I might buy Omega Ruby. My fault I know.But It goes too far. So I will wait to make sure they don't plan on making a Delta Emerald before buying ORAS.