Lets see if I can justify those who got left out of CaP OU (thanks Kammen):
In Standard but not CaPs' OU
Alakazam
Revenged by Strata and many who whoudl use it could be inclined to pick Strata over it. Rev can kill with SS, Syclant outsped for most of the month, Oak could take its attacks, beats down Fidgit.
Only just made normal OU.
Not a surprise.
Breloom
Yea.. Loom really hates every CaP for a different reason.
Not a surprise.
Cresselia
Wait what? Well Ant can 1KO after a TG (close with just LO), Rev can set up on it under some conditions, Oak stalls it to death (even CM).
This is a bit unexpected as it is decent against some CaPs and a solid OU in normal, but oh well.
Donphan
Barely in normal OU. Rev/Oak/Ant/Strata setup on ot beat it.
Dragonite
Little odd but Oak can wall for a while as can some Rev. Strata and Ant may be able to revenge under some conditions.
Dusknoir
Revenankh all but replaced it.
Electivire
Walled very badly by Oak, never was that good in normal.
Fortress
Can't wall the top Physical threat (Rev) and is set up bait for it. Rev also blocks Rapid Spin. Fidgit can encore and set up on it, Oak can wall and 1KO. Many Strata have a fire attack.
yea I can see this one.
Gallade
Flying attacks give it a hard time? Dunno about this one really. Never used/played against it much so I don't know what it has problems with.
Ninjask
Less noobs?
Jolteon
Walled by Rev/Oak/Fidgit. Strata may take its team spot as fast special sweeper.
Rotom H and W
We have Rotom A which includes these.
Snorlax
Rev/Strata/some Fidgit setup bait, Oak can normally cripple. Still I would expect it to scrape OU but evidently not.
Weavile
Oak walls, Strata revenges, Rev can set up on some sets. Tar is better for Pursuiting/sweeping normally.
Yanamega
Really? I always thought it would do decently in CaP.. Flying is such a good STAB here.
I suppose Strata could avoid a 1KO and revenge it, Rev.. dunno really. I think Yan would win with flinchhax normally.
Oak would be close, nether could switch in. Fidgit could hold it off for a few turns.
And as we have less people we can't try out as many Pokemon as normal or switch teams as much. Therefore will will have more "backround noise" and our meta will appear more centralised.