Blood for the Blood God, Skulls for the Skull Throne.
In another post about balance, the subject of Khorne and the World Eaters came up, along with debate about how being psycho-surgeried loonies naturally attracted the legion to the Brass throne.
The fact is, Khorne cares not from whence the skulls come, nor from whence the blood flows - as long as it does in his name. His only moratorium is that it must be done with martial prowess and skill, rather than slinking magic. Hence no spell-casting/psykers.
If you look at Realm of Chaos - Slaves to Darkness, it is mentioned in the fantasy bit that Khorne isn't against magic per se - its the use. Fantasy used to include the award of daemon weapons, including Chainswords and Autoguns - this was highlighted as being magical items, as are Brass collars of Khorne and Bloodstones etc. Using magic items good, using magic itself and separating the warrior from the kill wwith skill, bad.
In the same way, the Worldeaters army list mentioned how the devastators were just as honoured for the long range death they could bring. This was perfectly acceptable. So to answer the question, a chaos codex could represent worldeaters easily, with devs/havocs having MoK, the translated tac marines being CSM squads with MoK and banners of rage (or is it wrath) and the real teeth of the legion, the assault squads, as being the berzerkers.
This can/could be done with probably the last 3-4 codexes.
The old fluff mentioned how the legion retained its librarians, who went backtotheir role of battlefield comms and recording the chapter history, ie the amount of kills tallied - relinquishing the psychich powers. You could argue this (and the fact they maintained chaplains and techmarines) has been retconned, but unlike 6th ed SM codex ensuring characters are specific to chapters, anyone can take a dark apostle, no?
So to sum up, equally acceptable to Khorne/World Eaters to use long or close range, the latter being preferred. The World Eaters did not have a massive loss of IQ upon entering the EoT and instantly drop a legion's worth of heavy kit to retian only assault loonies, and even post Skalathrax warbands would not have changed, using mainly assaulters but with a healthy mix of long range where necessary.