Depends. I think they should definetly put in a Warboss class just to ensure Orks don't end up at a disadvantage (I seriously doubt they'll be the most numerous faction, even with F2P boyz, Space Marines will probably be the most popular) that would cripple them as a faction. I don't see why a Warboss class would cause any problems, just make sure that all non-hero Warbosses don't have access to mega armor. Similar to the Warbosses in DOW II, they just have their biceps, a kustom shoota, and a chainaxe.

Gotta only be one warboss. If more than one warboss was allowed, it would be almost mandatory to kill each other until we had only one.
How's that for picking a faction leader?

Nobz are going to be in the game. They can act as a leadership unit with some buffs as well as being tough choppy or shooty bastards. No need for the Warboss Tide.

Maybe in addition to earned classes, there could be a socially unlocked class. Like Boss for the Orkish equivalent of a Strike Force (A Mob?) . Accessible only by the commander of that Strike Force - you could do the same with SMs and CSMs (Brother-Captain and Champion respectively) or Eldar (Autarch maybe, or maybe just an Exarch).

The thing is though is that players need a combat commander I think if your going down social unlock route make it a captain/insert factional equivalent here any ways the reason it should be a captain is because strike force commanders should be leading from behind the lines calling down support and sending objective locations and dropping in reinforcements and supplies not running up and punching or shooting or menial buffing. I agree with the social unlock theory it works and complies with lore making everything be alright for a nob captain class coughcoughnotawarbossclsasscoughcough