True, but that would take time and what characters can they build up that can stand shoulder to shoulder with the Alliance ones?
I mean outside giving thrall his power back is there anyone else who come close? Maybe Loa Vol’jin if it becomes a thing.
A single book or comic wouldn’t be enough, which I would expect a few novels or a whole comic series exploring the Horde rather than the Alliance focus they normally get.
That way they can bring these characters and plot threads into the game in much earlier expacs rather than the Horde following the Alliance around stopping the Void.
You also have to remember that the Alliance cannot be put on the backburner for content in game while they focus on rebuilding the horde. They need to keep the game development balanced.