What I meant is that whoever becomes warchief, they'll end up sitting in that throne instead of somewhere else. There are certain fixated standpoints within the faction story that Blizzard isn't changing.
Lordaeron being ruined beyond the level at which it already was is just a circumstancial thing that doesn't change much as she is in Orgrimmar during Legion too.
We could now say that Blizzard is making the Horde revolve around orcish assets all the time because of this, as each warchief was forced into the same throneroom. That wouldn't be true though; Blizzard is doing it because of the versatility it gives to the story, just as making a human lead the Alliance gives versatility to the Alliance.
If a non-human character is made to lead, then they narrow down their options to the ways we know these other characters from the past. The only thing they can do then is go along with the character's traits as we know them - which narrows possibilities down - or they can crap all over established character lore(hello Alleria, hello void elves) and look inconsistent.