I doubt it'd be that bad. It's not like the council members will have a factionwide voice chat they'll use to mouthbreathe on and condemn everyone as worthless noobs because you didn't want to go to the objective they designated. I expect it'll take a decent amount of effort and co-ordination to do really well in campaigns, and it will be frustrating a times when you're losing, but anybody whose style of leadership is unpopular will quickly find themselves being ignored in favour of someone who isn't a 'megalomanic prick.'

I can think of a few loyalist players that already fit into the megalomaniac category

Let the forces of all gods and factions come together so that we may prepare for carnage to come aslong as I get a seat at the BRONZE TABLE OF KHORNE that is

To the gladiator pits time who will dare to challenge the gladiator king the world eaters primarch

Brothers, please. This does not have to decided by pointless sparring. Rank and merit should be the deciding factors. The Hierarchy should be divided like so.
Grand Warmaster: Has final say in operations and is the overall leader.
Siege Master: Will have explicit command over heavy vehicles for troop support and securing vital objectives.
Master of First Blood: Commands fast attack vehicles and units like Raptors. Coordinates strikes on enemy convoys and flanks.
Infantry Commander: Leads the bulk of ground forces.

From this 4-man Command Council, all decisions of war can be made. From here, we build a leadership network down, all the way to Squad Leader. We are blood-mad fiends...well, most of us are. But we must have a level of decorum in this crucial crusade.

I agree with this statement but I do believe there also needs to be advisers for each of these high commands.

It's just the bare-bones framework of the Chaos command structure. Of course the 4 members can recruit the most veteran/elite to be their advisers.

Well that being said, how many can be advisers? I already know that they should have an honor squad with them.

I demand world eaters be at the front of all attacks and make sure the slannesh stay away from us we may kill them but yeah i agree with thalias command structure also there should be dark chaplains as advisor to each of the ranks in the command structure

Well as advisers go it would be the sorcerer because all the Chaos legions except the Word Bearers killed their chaplains unless I'm wrong on that aspect.