What if the future of WoW is that The Alliance and Horde are no more and it becomes more about your race. That's where your pride is. There can still be alliances between races but Blizz wouldn't be forced to make all races get along in the end.

And just so it doesn't "break the game" instead of being split between Alliance and Horde you are split between Kalimdor and EK. That is what unifies you when there is a major threat to where you live and you all come together if it's a threat to Azeroth itself. Places like Org and SW just turn in to cities for anyone to visit (even Orcs in SW or Humans in Org)

Seems like we could already be headed in this direction with them destroying Darnassus and Lordaeron. They just have to figure out what to do with Exodar and Silvermoon but I suppose it's not impossible. Exodar is just a ship anyway so all they have to do is move it to the other side and as for Silvermoon it would be a little more tricky but with their obsession with magic and the help of the Nightborne I see no reason why they couldn't Dalaran the whole place over to Kalimdor or just teleport it.

And instead of being hostile towards each other for being Alliance in Kalimdor or Horde in EK people are just suspicious of you and waiting for you to make a move and the second you do that is when you get flagged for PVP. The difference here is that you are held accountable for your actions rather than automatically attacked because you are either Horde or Alliance.

This is the best way I can think of for how you can get rid of The Alliance and Horde without breaking the game. You are loosely united by continent.

Instead of saying "FOR THE HORDE" you would say "FOR THE FORSAKEN" or whatever that chant would be for what your race/tribe is.

As for old references to The Alliance and Horde for old content that's just the past. When you level through it you are leveling in the past when there still is a Horde and Alliance.

As for the lore explanation of battlegrounds I guess you could either say that they also take place in the past or that the continents put together a team of their best fighters to take on the other continent and it's more of a thing for fun like the Olympics or something only also kinda like a gladiator type thing where the losers die.

As for allied races I would say that even though not all of them live in Kalimdor or EK maybe the requirement to be a allied race is that they have to be closely connected to something on either Kalimdor or EK so they are allies of another race rather than being allied to a entire faction. Like the Draenei & Lightforged Draenei or Nightborne & Blood Elves.

I think I covered everything. Either that or maybe they just create new factions. Half the Horde stay Horde, half get split off in to something else in southern Kalimdor, half the Alliance stay alliance and half split off to something new in northern EK. 4 factions instead of 2. But that's only if they don't want to kill factions entirely but I do agree that we can't keep doing Alliance and Horde forever. New factions either need to be created or they need to kill factions entirely and just get back to having your race be what matters.