In a Chaos Renegade Space Marines codex you would have armament more similar to "modern" Space Marines but be able to gain, buy, Chaos type upgrades based upon how deeply your chapter has fallen into heresy. Sound complicated? Not really, 5th ed codices have had more and more options be unlockable by HQ choices, with a Renegade book you wouldn't even need Named Characters. I know this system wouldn't be perfect but thankfully I don't write rules for GW, even if sometimes I could write tighter ones than they do! Think of an escalating Chaos Renegade army list like this.
Level 1 Renegades:
HQ: Captain/Chapter Master/Librarian/Chaplain
This army may take 0-1 basic lesser daemons as troops and Chaos Undivided Icons. Units in this army are Fearless as long as the Sergeant is alive. Either the Librarian or Chaplain can summon Daemons as if they are icons. Chaplains in level 1 Renegade chapters may take 1 Psychic power, Librarians may choose 2 powers from C:SM or one power from C:CSM.
Level 2 Renegades:
HQ: Captain/Chapter Master/Librarian/Chaplain, these choices may take a Mark but all units, including other HQ choices, in the army must be unmarked or have the same mark as the HQ choice. Librarians may take 1 power from C:CSM in addition to their normal powers. Chaplains and Librarians act as icons for summoning Daemons, Chaplains may take a psychic power from either C:SM or C:CSM.
Units in this army may take any of the 5 marks for 10 point per unit. Khorne +1 Attack, Slaanesh +1 Initiative, Nurgle Feel No Pain on a 5+, Tzeentch 5+ Invul save or +1 to Invuls better than 5 with a Maximum of 3, Mark of Chaos Undivided Units are Fearless. This army may also take 0-3 Daemons from the Troops section of C:Chaos Daemons.
Level 3 Renegades:
|Hey, I thought about Khorne, now I am a World Eater!|
Units in this army with marks benefit from the following Gifts for 10 points. Khorne Furious Charge, Slaanesh +1 Initiative and Rending, Nurgle Feel No Pain on a 4+ and Defensive Grenades, Tzeentch 5+, or 1 better, Invul save and Aspiring Champions may choose one psychic power from either C:CSM or C:SM, Mark of Chaos Undivided grants Fearless and Aspiring Champions have the Winds of Chaos power. This army may take 0-3 Troops and/or 0-1 Elite/Fast Attack/Heavy Support units from C: Chaos Daemons
Level 4 Renegades:
HQ: Chaos Lord/Sorcerer/Daemon Prince. These choices, except the Daemon Prince, may take a Mark but all units, including other HQ choices, in the army must be unmarked or have the same mark as the HQ choice. Units have Aspiring Champions, not Sergeants. Armies that take a Daemon Prince must choose one of the marks and all units must have that mark.
Units in this army with marks have the same benefits as level 3 Renegades. Armies that include a Daemon Prince may choose 1 of the Traitor specific Units that fits the mark of the Daemon Prince. These armies may take 0-2 units of Daemons from the Elite/Fast Attack/Heavy Support choices in C:Chaos Daemons, and 0-4 choices from the Troops choices. Obliterators and Defilers may be taken.
I have some major gripes with the current Chaos Space Marine codex. The top two are this:
1. The Traitor Legions take a huge back seat.
2. The Renegade Chapters take a huge back seat.
It is a codex that doesn't do justice to the Chaos Space Marines, of any type. Overly simple and sweepingly benign, C:CSM is utterly underwhelming at every turn. By splitting the codices into two types, Legions and Renegades, we can benefit from diversity in game terms and bring a bit of the diverse reality of Chaos Marines in the fluff to actuality on the table top. There is nothing I would enjoy more than being able to customize my Renegades based upon the level of corruption of their leaders, after all isn't that how it would truly be? Think about the Soul Drinkers, or Dark Angels, or even the Traitor Legions; how did Chaos spread through those Space Marines? The corruption of Chaos spread slowly, it didn't happen overnight. That's what I want to see in my Renegade army.
So what do you think, should the next Chaos Space Marine codex be one book or two? Do you think Renegades and Traitor Legions can each be given a fair shake if they are in the same codex?