Hm... wonder if GameFreak will be pattern-breaking again, as they did in XY. If so, it might be that we won't get a faithful remake, and more like a Hoenn revisit or something. This might mean total redesigns of several areas, new characters (though this is definitely to be expected anyway) and perhaps even changing the order of the gyms. Then again, neither FRLG nor HGSS were that drastic, so I guess this isn't to be expected this time either.
Either way, I guess new areas are to be expected. Caves housing legendaries that weren't in the original games are practically given. A new town/other area is a pretty safe bet too. Hoenn never had much in terms of post game areas, so it's a safe bet that some island, somewhere, will be opened for further exploration. Or perhaps the Battle Frontier island will be enlarged a bit.
Also, if they return to the Secret Base system of RSE, I'll be wanting to travel to Japan and break into GameFreak's locales just to give the designers a hug.
Lastly, allow me to be negative when it comes to tutors. Traditionally, remakes haven't focused much on movepool expansion compared to the first games in the series. HGSS famously featured almost no changes to movepools from Platinum. I think we'll have to wait for Z before we'll see massive movepool overhauls, such as those brought on by Platinum.
EDIT:
Don't know why people assume that Kyo and Grou will get a mega. I'm not saying that it's impossible, but there isn't the slightiest hint for that, right now.
To be fair, we don't have much to go off. Preliminary boxart doesn't exactly give away much. There isn't the slightest hint of anything yet.
And besides, do you really want that? They're already ungodly powerful, especially Kyogre.
Well, so was Mewtwo...
