Just a quick summary of how I view the metagame:
the water/fire/grass core died as soon as the new list was announced, so the whole metagame revolves around ghost, dark, normal, fighting and psychic.
Bulky normals are the best sweepers out there right now, especially physical ones, since everything is packing mass SpD to take a hit from the ducks.
Raikou has pretty much been a non-issue. everything either has enough SpD and attack to not let it set up, or EQ/Encore/Trick/Taunt, which it doesn't like
Leads have boiled down to Ambipom, Pixies, Froslass, and bad, with a few rare exceptions (A Clefable and a Moltres are the only ones who have ever made me worry about the lead). I actually blame Uxie more than anything, as most leads that beat ambipom/froslass do nothing to Uxie, who sets up for free on almost anyone without a really fast Taunt/ridiculously powerful Crunch.
CB Spiritomb vs any Alakazam is about as one sided as Tyranitar vs Shedinja with stealth rock in play.
Cresselia needs to go, porygon can be tested more (Spiritomb and Registeel are both great checks), but Cressy can do too much.
Right now I'd say suspects are:
Porygon-Z (under offensive characteristics of broken)
Froslass (under support characteristics of broken, though personally I don't think she's BL)
Uxie (under support characteristics of broken)
Cresselia (Under all characteristics of retardedly broken)
maybe Moltres, though I think the SR weakness more than balances it out
since everyone else can write paragraphs on why they think Cressy/Froslass/Pory need to go, I'll explain Uxie
Support Characteristic
A Pokémon is uber if, in common battle conditions, it can consistently set up a situation in which it makes it substantially easier for other pokemon to sweep
Lead Uxie can either be Trick Scarf, or some combination of Screen/SR support with U-turn, Memento, Psychic (/zen headbutt), T-wave or Yawn filling the rest of the slots.
Trick Scarf immediately cripples most scarfless-leads, as they're locked into one move, usually with Uxie free to do what it wants afterwards (occasionally taunted). If it avoids the taunt, it can setup stealth rock and provide paralysis support due to the forced switches, good speed and amazing bulk. If it gets Taunted, it U-turns/switches out to a counter while the now-scarfed pokemon leaves due to it being stuck on taunt.
More standard Uxie leads have problems with faster taunts, but can setup dual eather or any one of its other useful filler moves, preventing very many safe switch ins.
sounds like a normal good lead right? here's the kicker. Unlike other setups leads (froslass), Uxie has absolutely NO TROUBLE coming back in at almost any point in the game, as it can take the ever common fighting and ground moves no problem, as well as any move coming off a lowish stat, like a bulky water's surf. once in, it has the speed to set up one screen before the opponent can do anything, and the bulk to take a screened hit while it sets up the second screen. and normally it can take the second hit and either paralyze the opponent or use memento to cripple them/force a switch while your new pokemon sets up. while this wasn't as much of an issue in previous metagames, the setup sweeper threat list has been slowly building, so screens now allows the following to set up effectively for free (in alphabetical order):
SD Absol
RP Aggron
DD Altaria
CM Cresselia
SD Drapion
SD/DD Feraligatr
NP Houndoom
SD Kabutops (ironically Uxie can also set up rain)
SD Leafeon
CM/NP Mismagius
NP Porygon Z
CM Raikou
RP/SD Rhyperior
Sceptile
SD Scyther
Swellow
SD/NP Toxicroak
and that isn't even counting RD (which uxie is also capable of setting up) sweepers like Omastar and Ludicolo, or NU sweepers like SD Ursaring or SD Pinsir (or DD crawdaunt, but I've yet to see that done, so i'll reserve judgement on that). and everything on that list has a very good chance of sweeping when it has screen support and a crippled pokemon to set up on.
Uxie has too many options to set up too many sweepers, so I personally consider it more suspect than Froslass, and much more suspect than Raikou.
But then again, we'll see what happens when ccresselia is out