If this was a suggestion thread, it would be in the suggestion section or the Game level and design section. Since that's where the devs usually look. The main reason to chose Chaos Marines over Space Marines is mainly for the daemon weapons, or the chainaxes, or the manreapers, and the many other Chaos weapons. Personally, I find melee more satisfying then then simply firing a bolter.
Two axes each containing the spirits of a Bloodthirster, Great Unclean One, Keeper of Secrets, and a Lord of Change
It would be hard but packs of daemons have bean used but never from different gods and never so many greater daemons
You also need an Abaddonian level of being an absoloute complete bastard inorder to control a weapon infused with a greater Daemon...I think controlling multiple GD is something only DP's can do.
I really hope there's an execution move where you can open an enemy up with lightning claws and pluck there heart out and eat it. After all it's highly nutritious!