Not forgetting about factions, no. But not making them the main focus of expansions. Develop them in new zones or by revamping old zones one by one, like cata but slower. Not everything has to be a full high end area. What's stopping Blizzard from implementing a questline, where Loch Modan dam is being rebuild? Could be a max level quest, giving some minor form of currency, could also be a quest you get after completing the major questlines in that zone. You don't have to invent much, you don't need to make this a zone like Korthia or ZM. A simple questline, much like the Nightwarrior one, just without any relevance to the current main plot.
BElves get one next patch, DI Dwarfs, too. Do that for every race, bit for bit. Bigger events involving multiple races/factions can still have more screentime.
But to be a realistic world, every race must have their own, independant agency. Currently the Stormwind humans decide all diplomacy for Dwarfs, Night- and Voidelves, gnomes, Gilneans, Kultiran and Draenai. And Trolls, Tauren, Goblins, Vulpera, Nightborne and Bloodelves were represented by either Orcs or Sylvanas.
And as long as player factions exist the story can't be told in a reasonable way. Players are the only reason the Horde is still united. And the Alliance leaders must be written like fools to keep it that way.