I'm gonna write a list of all the things I'm excited about for Omega Ruby/Alpha Sapphire. I'll try to only list things that have been confirmed, but I may speculate a bit too.
-Mega Sceptile. Since Sceptile was my first level 100 Pokemon ever, and really marked the start of when I got into Pokemon, I have loads of nostalgia for it.
-Contests. Need I say more?
-Cycling Road. In the original games, it was possible to do a perfect run of it (9.15). With the new bike mechanics introduced in XY, that will become pretty much impossible, meaning that getting a great time will be that much more rewarding.
-Diving. And not the lame diving to the Abyssal Ruins in BW, but proper diving onto the seafloor.
-Secret bases. I just love them.
-The Sky Pillar bike puzzle, aka the most
evil fun overworld obstacle that we have ever had.
-Mt. Chimney. That place will look AMAZING in 3D.
-Route 113 and Mt. Pyre. I can't wait to hear the remix'd music.
-That mysterious dark area above Lilycove City. Darkrai? Giratina? Deoxys? Place your bets!
-Mirage Island. I never saw it in the original games, and I doubt I'll see it in the remakes, but you never know...
-The possibilities surrounding Regigigas. The one I think is most likely is that when you catch Regirock, Regice, and Registeel, you take them back to the Sealed Chamber and solve one more braille puzzle, and another door will open to reveal Regigigas.
-Automatic record mixing with StreetPass. Yes, this hasn't been confirmed and there have been no hints toward it. But I'm hopeful that it'll make it into the games. In the originals, there were so many features of mixing records (Secret bases, Frontier records, etc.), but to actually mix records you had to get someone to link up with you (requiring a link cable), and then go into a room to wait while the records mix. StreetPass would solve so many problems by doing it automatically.
-The presence of Mega Activators on Maxie and Archie. Now, that may not seem like a big deal other than they can use mega evolution. But let's think about it. In the original games, their team was Mightyena, Crobat, and Sharpedo/Camerupt. None of these mons have megas. This means one of four scenarios:
1. New mons, most likely Sharpedo and Camerupt, will be able to Mega Evolve. (Possible)
2. Maxie/Archie will have a 4th mon that will be their ace. (Probably not)
3. Ancient devolution will work the exact same way as Mega Evolution, right down to it being activated with the same stone. Maxie/Archie will use Groudon/Kyogre in their final battle against you, sort of like N did with Reshiram/Zekrom.
4. Maxie and Archie cannot use Mega Evolution, and TrollFreak just put the stones there to mess with us. (Always a possibility)
But I swear to Arceus, if finding Feebas is as annoying as in the original games...