The Horde Is not the Horde without a Warchief It's so dumb I hoped It wouldn't be true.
I don't want a damn council to follow, The Horde's races share spiritual beliefs, they're outcasts who band together, people with common beliefs and even uncommon ones. And Orcs of all people who are at the center of the Horde are Warlike, It's this historical thing of when you're at peace for too long you become stale, weak and brittle. Fighting all the time, always improving, strenghtening and fighting keeps you prepared for the innevitable attack on your borders, like, The Alliance.
And Orcs know nothing but war, that's who they are, they fight and they're proud of It, all of the Horde races are like that for the most part, trolls, tauren, orcs they all know war and are not afraid to wage war and then settle for peace but still remain with a Warchief at the lead to keep It's population ready for war. The way MoP and BfA showed the Horde was due to extremists who wanted to rule the whole world, well how about choosing your Warchief this time, properly. Thrall choose Garrosh and made a mistake, Vol'jin's ghost friends told him to choose Sylvanas and so he did (And nobody in the Horde questioned that It might just be his fel-corrupted body from the recent stab wound in his gut from a fel glaive).
So to me, having a council now doesn't make me even proud to be Horde anymore, what will I yell? FOR THE COUNCIL! when I charge into battle? Meh. And also this puts an interesting question on the table, will the Alliance be demanding a council too now, instead of a High King of the Alliance? Would be odd If the Alliance didn't see this happen and think "Maybe we should have a council of competant military veterans and advisors instead of a young lion king who barely knows how to lead in the first place"
I think this council thing fits the Alliance more, an Alliance after all, right? Where each kingdom's leader has a say in everything, the Ironforge Council, Tyrande/Shandris/Malfurion, Anduin, Panda girl whatever her name is, Gnome King, etc. right?
But the HORDE Is a HORDE with a single leader under it, If not we'll become... what, a commonwealth, a red alliance? It's so dumb and takes away further identity of being a proud Horde member.
Lastly, with the 8.3 spoilers datamined and such, we see Tyrande basically going Sylvanas on the Alliance, a basic copy of Sylvanas but in the Alliance now.... they're so unoriginal they can't even come up with a good conflict within the Alliance other than "Tyrande goes abit mad" like most people seem to go mad, one expansion it's Alliance, one It's Horde........... althugh for the most part It's the Horde lets be honest cause we're the baddies, right?
Last last point to make, seriously wouldn't this make the Alliance consider a council too? Historically speaking It'd be like the French Revolution spreading ideas to neighboring kingdoms that "Maybe a Monarch/single leader isn't needed after all" and I'll be so shocked If there's no division in the Alliance due to this at the very least.