Overall, it appears that Phil Kelly is trying to make the Chaos Codex a bit more flexible and allow for a very customizable army in several formats. Without seeing all the rules, the following is just impressions from what I am reading.
The Boon Table: Cleary GW wants Chaos to be a possible Character Hunting army and they are pushing the challenge rules now trying to make more of a splash in the game with them.
Warlord Traits: Other than the infiltrate options the others is rather limited and taking a chance to roll on Personal or Strategic would be more ideal.
Mechadrites: two bonus attacks? No power fist, ok….not bad. A meltagun and flamer? Yea! Beats the crap out of a plasma pistol!
Seal of Corruption: An obvious thing for the Dark Apostle!
Gift of Mutation: This could get ugly if you had multiple ways to cast this power to buff up characters. I hope this is limited to one Gift roll per turn.
Wizard’s Familiar: Personally I would have called it Sorcerer’s instead, sounds like Fantasy too much. Still, reroll psychic powers tests. Hrm…not bad.
Steed of Slaanesh: Outflank and Acute Senses, wow there is a character hunter. Add to a unit to give Outflank and enjoy!
Icon of Revenge: Fearless, now that is better that rerolls!
Icon of Flames: Heavy bolters can get soul blaze? Wonder if they can get AP3 ammo like bolters and pistols? *drool*
Icon of Rage: Nice but not as good as the others. The loss of +1 INT sucks.
Icon of Despair: Fear, meh…
Icon of Excess: Feel not Pain, if it does not cost too much, this is a nasty upgrade.
Demon of Nurgle: Getting Shrouded? Wow, cover save city if he is in the right spot. Feel No pain would just make this guy sick.
Demon Engine: Ok, amusing eats your own men on a 1, heals one Hull Point.
Maulerfiend with Magma Cutters: Sounds like this guy is designed to crack open armor, monstrous creatures and fortifications.
Obliterator/Mauler Weapon Morphing: Can only use one type, and then change to another on the next turn. They got Assault Cannons but no Missile Launchers or Autocannons? WHAT?
Master of Machines: Heal vehicles or Curse giving Gets Hot to a vehicle. Wow, that could be nasty. Oh Flyer…here has this…..yes, go on and shoot all those weapons.
Psychic powers: Most are either high AP or AP 4 or less….some buff, mostly curse with a sprinkle of other powers.