Chaos Space Marines: Leadership and reliability

The background to the question

So, there's been quite a lot of rage on the internet recently about the Black Legion Codex release, which stems back to the belief that Chaos Space Marines need 'fixing' as a troop type. This belief stems from Chaos Space Marine Leadership.

The perceived problem is that with normal leadership and no special rules, such as "And They Shall Know No Fear" or "Fearless", Chaos Space Marines run away too much, particularly from lost hand to hand combats when their unit leader is forced into a challenge he has no chance of winning. Icons are dismissed as being too easy to snipe from the unit, and Veterans of the Long War as being a simple Leadership boost without adding a special rule.

I'm not going to comment on the mechanical advantages and disadvantages of Chaos Space Marines, as while I have the Dark Vengeance set and I'm planning a few CSM allies for my Guard at some point, I haven't played them yet, so I'm not really in the best place to comment on the in game mechanics.

However, several people have said that this does not fit their view of the background and setting of Chaos Space Marines. Why would ten thousand year old veterans be 'less good' than recently recruited Loyalist Marines?

My take on the situation

The Leadership statistic represents courage and discipline. Loyalist Space Marines are psychologically indoctrinated and hypnotised into fanatical loyalty to the Imperium. They "Know No Fear" because they have been brainwashed. Even that aside, their bravery on the battlefield is about having a higher cause. Leadership checks the point where you are ensuring that your perfectly natural human reaction to flee a dangerous situation is being over-ridden by your desire to stick to the plan.

Chaos Space Marine cult troops (Berserkers, Noise Marines, etc) are Fearless because they are dedicated to a 'higher power'. They have subsumed themselves into another concept. Plague Zombies are Fearless because, well, they're zombies. Chaos Cultists are expected to run away a lot, unless whipped into line by a suitable agitator.

So, why do "normal" Chaos Space Marines run away?

It is because they are evil.

This is actually a deeper statement than it first appears. The point of a Chaos Space Marine is that they have overcome their original training, loyalty and conditioning to a 'higher cause' (the Imperium). Instead, they have taken a more selfish, personal path to power.

The key word there is selfish. Chaos Space Marines are not the sort of people to lay down their lives for a cause - if they see things are going badly, they will quite likely start doing their own thing, which is likely going somewhere safer. Renegade Chaos war bands are not places you are likely to see loyalty to the bitter end and self sacrifice for some higher cause.

In short, in the case of a Chaos Space Marine, or even a Veteran of the Long War, their willingness to give up and flee is nothing to do with how skilled they are. It is their self centred nature to want to continue existing, even if it is at the expense of some superior's plan or the course of some battle. They have had ten thousand years to plot revenge in some cases - so why throw that away for the sake of a battle plan that appears to have been conceived by a twelve year old child (because sometimes, it was)?

From a setting perspective, the Chaos Space Marine stat line is perfectly fine. The real question is about game balance and points costing. I think, for Games Workshop, at the moment that takes second seat to 'Forging the Narrative' - and the scores of treacherous little mini Starscreams in power armour are doing that just fine.