If you read the posts though from the guy he seems to be Spanish I believe, and I think a lot of people have called the things you attach to your reclamation legion (what is a formation) as formations. In the majority of the cases that is true, the Royal Court, Judicator Battalion, Destroyer Cult, Canoptek Harvest, Annihilation Nexus, Living Tomb, Deathbringer Flight all are Formations listed in the codex. However the Flayed ones, Deathmarks are not, and the collective group of that is listed as Star-God also are not a formation.
In actuality all these things in the form of the Decurion are called Core (Reclamation), Command (Royal Court) or Auxiliary (everything else listed above). Each of these things in the Detachment is treated in the same way as your traditional HQ, Elite, Troops, Fast Attack, Heavy Support, Fortification and Lord of War. The only compulsory choices in the case of Decurion is 1+ Reclamation Legion, Then you must take a minimum of 1 and max of 10 Auxiliary choice & the option of 0-1 Royal court per Reclamation Legion (both Auxiliary and Royal Court).
Personally this reminds me massively of the old Tyranids in Space Marine (before it was rebanded again to Epic 40k). They basically had their starter hex card of a Dominatrix, That had an arrow pointing out of every direction of the hex. You then could attach any hex card to her. All other cards had an input arrow pointing in from 1 direction and some of these cards like the harridan had a single arrow pointing out, while Hive Tyrants had 3 exit arrows. Most cards however had no exit arrows so ended the chain.
In essence it was a great new way to have an army design and if you lost your link the start card you ended up reverting back to instinct rules rather than having full control over your stuff. What basically meant that melee things tended to run the shortest route they could to the nearest enemy, firing ones shot the closest thing they could fire at.
In either case I think I prefer the new Decurion style of army lists than the current 1-2 HQ, 2-6 Troops, 0-3 Elite, 0-3 Fast Attack, 0-3 Heavy Support, 0-1 Lord of War, 0-1 Fortification.
If you actually look at the Decurion as a whole you have 1HQ, 0-2 Elite, 3-12 troops, 1-3 Fast Attack & 0-3 Heavy Support to start you off for the Reclamation Legion, though the options of what you can take is strictly limited. On top of this you take an Auxiliary what could be as simple as 1 Elite to 1HQ, 3Fast Attacks and 1 Heavy Support.
Most of these 'Formations' or Auxiliaries seem to have some form of special thing that is themed with the army and some even have potential drawbacks of having to take something that normally under min-max / WAAC circumstances you would not even consider.
The other thing to add to that is that they have access to Lord of Skulls. But that was not mentioned in the formation section that was listed by that poster.
The odd thing I said before about this is that these special detachments can't have Fortifications by the looks of it.
Last edited by mayegelt; 03-23-15 at 11:15 AM.