Considering they don't still print the Eye of Terror codex and it's not particularly clear how long the Lost and the Damned will be a valid build, it wouldn't be terrible to have something like this available to Guard Commanders:
Traitors: The regiment serves the ruinous powers of Chaos! Mutants become an Elites choice (as the focus is on the traitor Guard regiment, not any followers they may have picked up), while Commissars and Priests cannot be included in the army. A Traitor army cannot include allies taken from either Inquisitorial codex, nor may they be used as allies for an Inquisitorial army. Instead, Troops choices and summoned daemons from Codex: Chaos Space Marines can be selected as allies, filling an Elite Slot in the case of the Chaos Space Marines, or a Troops slot in the case of summoned daemons (which is a change from the new CSM 'dex, but allied units really should take up a slot SOMEWHERE.) May not be selected with Grenadiers, Independent Commissars, or Xeno-Fighters.
Tank Aces: The crew of the formation's armoured vehicles are either veterans, uncannily lucky, or trained to a higher standard. Any armoured vehicle may choose a Tank Ace to command it for +20 points, or +30 for a model with one or more AV14 facings. Once per game, a Tank Ace can force the opponent to re-roll the result of a penetrating hit against his vehicle. This cannot be selected with Drop Troops, Jungle Fighters, or Warrior Weapons.
Big an' Mean: The regiment comes from a world where Ogryns have naturally evolved or are bred. The regiment is either entirely composed of Ogryns or contains a disproportionate number of them as a result. Ogryns become a Troops choice for an army with this doctrine. Cannot be combined with Jungle Fighters, Carapace Armour, Light Infantry, Drop Troops, or Chem-Inhalers.
Space Marine Traits...
I imagine Space Marine traits are going to go the way of the dinosaur in the not too distant future, but what the heck.
Knowledge is Power: The Chapter includes a higher number of Librarians than normal. To represent the scrying and bookish nature of Astartes Librarians and the strength of them in numbers, if the army includes one Librarian, it adds +1 to its Strategy Rating. If it includes two Librarians or more, it adds +1 to its strategy rating (not cumulative with the aforementioned bonus) and allows one dice to be re-rolled per turn of any sort. Remember that a re-roll cannot be re-rolled!
Unrelenting: A Chapter with this Trait relishes close combat over ranged fighting, and are particularly relentless in its pursuit. They ignore negative modifiers for being outnumbered in close combat, and are Stubborn within 12'' of an enemy model.
Descent into Madness: One of the Astartes of the Chapter has become corrupt, and his words have reached the ears of many of his brethren. Tactical and Assault Squads may purchase an Icon of Chaos (see Codex: Chaos Space Marines (the new one)), but if they do so, they become an Elites choice. An army which has chosen this Trait cannot include allies, and may not select We Stand Alone as a drawback, as the effect is already there.
Love Thy Neighbor: The Astartes are quite at home fighting alongside other forces of the Imperium, or deviate enough from the Codex to include human auxiliaries (which is not unheard of-- the Ultramarines have a standing army that defends Ultramar, for example.) Any friendly Imperial unit (whether in your army or not) may use a Tactical, Assault, or Devastator Squad's leadership within 6'' if it is better than their own.