This gen is gonna see a lot of highs and ups. I wanna get to what I think might be in the next gen in terms of OU. I know it's just gonna be me rambling on about what may or may not be but I got to thinking a lot of the future. This is what me and a bunch of friends came up with.
The fall of steel types not named Lucario
Metagross and Jirachi are pretty much SOL in X and Y. With the new type chart into the next gen ghost types are gonna be ridiculously popular and these two are plagued with the typing of Psychic/Steel type. While this helped in Gen 5, it means that this gen they will be super effectively weak to two things. Also, other steel types such as Cobalion, Bronzong, and etc. will start to lose their edge even more thanks to the newer system. Another problem will arrive with the fact that Gen VI is gonna bring some more grass types. With that comes more fire-types entering in like Victini or Infernape making all the steel type's situation worse. Only a handful of steel types will be unaffected by this. Scizor is still gonna be a threat because of it's awesome Bug/Steel typing but will drop slightly because of the lack of steel types roaming around and the supposed Drizzle nerf. Ferrothorn, while he loses out on some resistances is already bulky enough to take a neutral hit and retaliate back. Lucario is going to be unaffected at all mainly because he was already frail enough. With the popularity of Ghost types probably gonna reach a climax in Gen VI many of them will carry Focus Blast. But a problem with that is Lucario already outspeeds most of the competition anyway and what he doesn't outspeed is a problem that has happened in this generation already. (Most notably Gengar)
The rise of the Phoenix (Fire Type popularity)
Looking at the new pokedex entries, Game Freak is giving a lot of love towards Ice and Grass types this time around. With that, a lot of pokemon that already exist are gonna be even more dominant this time around. Victini, Infernape, and even Moltres comes to mind. Infernape will tear a lot of the competition with it's trademark Mix-Master set as not only will it able to tear through steel, ice, and grass types like he did in the past generations but now he will be able to tear through newer opponents that might become popular like Aegislash or Aurorus. Victini will probably crawl out for the realm of UU and enter in as OU simply because of how powerful Victini's moves are and how the face of the new OU in Gen VI will be slightly more..Green. V-Create and Bolt Strike are moves not to be trifled with. Other fire types like Moltres and Entei will enjoy their usage as more steel types will probably drop down to play in RU or NU. Despite a nasty stealth rock weakness they will rise up in usage and might even escape onto UU and better.
Unchained (Unchanged)
This is going to be a slightly boring selection as these guys are going to be massively unaffected by this change. Rotom-W will still be a dominant teammate, just now he'll have to watch out for 1 or 2 more threats and will probably be running Surf instead of Hydro Pump. Alakazam will be largely unaffected by this because as said before with Lucario concerning ghost types. He already outspeeds most of the competition and can retaliate easily back to opposing Gengar, Cofagrigus, Aegislash, etc. Keldeo is unaffected simply because of it's typing. Water-Fighting is a double edged sword and in this case with the slew of newer pokemon coming in will make Keldeo mostly unscathed despite possibly ditching one of it's most powerful moves.
Retired Ideal Pokemon
Hydreigon sux now.
Okay, i'm gonna do this for real now. Almost all dragon types will immediately get the shaft when Gen VI sinks into servers for play. Nearly any dragon that was dominant before will now be limited to sets set to wall breaking. Course, we already all know this so i'm not gonna talk about it too much. Other niche pokemon that had weather niches will immediately start to drop and lose purpose. Dugtrio is a prime example as despite having a blazing fast speed base of 120, has a despicable Atk base of 80. Also with the rumored weather nerfings it limits Dugtrio's use even further to the point that it's a niche that if a team is running a weather team and not a regular weatherless team which will be the most popular in Gen VI. With that, a lot of weather based pokemon also get the shaft and are reverted back to being a niche pokemon. Tentacruel, Toxicroak, Venusaur, Stoutland, and even banned pokemon like Excadrill or Ludicolo will be half of what they were and won't be able to sweep as effectively. Given that they still can, it'll just be very unforgiving if they mess up.
And with that, that's just what I honestly think. Course, I maybe wrong and OU will still just be OU without any newer additions and just a lot of stuff going to NU, RU, and UU. We will figure out until Smogon figures out how the tiers will run this time around. Until then adios~
EDIT: I did read ahead of time and found out that weather is now reduced to 5 turns. So yeah...Uhm...Goodbye Politoed?