Gen 3 also saw a drastic change in the contest system, from a group of tents that you had to travel to, to one location because it wasn't good enough
We're not guaranteed to get any of these back, and with the chances of these games not being remakes but new game entities, they don't have any explicit reason to bring back those features even if we did like them.
Despite the incentive to visit Verdanturf Town, Slateport City, and Fallarbor Town being reduced a little, I think the Contest system thing change was more for convenience (it takes a while to prepare for Contests and I imagine that most people do one Rank right after the other, so everything being close in proximity offers convenience instead of the player having to fly around to other cities just to challenge a Contest rank).
Although there's no guarantee that Secret Bases will be back, I think they have a good chance of returning (they
were the one feature that enticed me to play
Pokemon Sapphire, anyway XD).
Wholeheartedly disagree. Pokémon is about fine-tuning a balance of features, and not shoving everything that's been developed since the inception of the franchise into a single game.
The Battle Frontier is a great example of something that's come and gone and re-appeared, and subsequently vanished once again in the franchise. Diving also went away, I'm willing to be real money that it'll make a comeback in ORAS.
I don't understand what you mean going through "the trouble of completely removing old features." What work does that require?? These games aren't being built off the tops of each other. Removing a feature has nothing to do with work; this isn't like carving out a building. It's 100% got to do with choice, and picking the right amount of features that suit a game, a region, or their console. Secret bases were unique to Hoenn and I absolutely think we'll be seeing them again.
I don't think everything in the history of
Pokemon necessarily needs to be shoved into one game
(but boy, would it be nice/convenient XD), but if Game Freak's going to fine-tune, they can at least preserve more of the good things. Apricorn Balls come to mind - to maintain consistency with Pokemon caught in Apricorn Balls in past games (
Pokemon HeartGold/SoulSilver), Game Freak has to code them into the games anyway (at least in terms of a Pokemon's Poke Ball "release" and "return" animations); why don't they make them purchasable in other regions (like how Sevii Isles salesmen can have Johto's MooMoo Milk)? At the very least, they would add to Poke Ball variety, and the "Ball-making mechanic" could still remain exclusive to Johto-based games. Regarding Battle Frontier, the Battle Towers (or similar facilities) and Battle Factories (since they mostly use the same Pokemon pool as the Battle Towers) should be present in all games post-
Emerald; they have no need to vanish unless one's trying to worsen the amount of post-game available.
But yeah, I think Secret Bases were a unique feature of
Ruby/Sapphire, so it's sensible for them to return as a feature again.