The problem with each new expansion is that Blizzard often neglects the world that has already been created.
There are talks about restoration of Undercity plague being cleansed and returning of Gilneas to the Gilnean people. A strong Gilnean people could be problematic for the Horde since Greymane did go after Sylvannas first chance he got in Legion, but Gilneas was one of the strongest human kingdoms at some point.
With talks of Dragonflight the concept of a “new home” has been introduced for Night Elves so losing old territories and obtaining new ones has been brought in.
Now that that allied races are a thing there could be more done to flesh out their place within the factions and the World of Warcraft as a whole.
For example, For the Zandalari Trolls the prophet Zul left quite a mess, so now that Talanji is now their queen she could send an expedition or effort to atone/make amends to the Pandaren people since the Zandalari successfully resurrected the Thunder King that defeated and enslaved the Pandaren people.
Zandalar was not not part of the Horde that stopped the Thunder King at the time. Neither Huojin or Tushui speak for Pandaren a neutral race.
Alliance and Horde has to have different goals. So for the Kul Tirans, led by the tidesages they seek out Immerseus to learn of alternative ways to cleanse the plague also restoration of plagued lands.
There is also the scar of Theramore. In which a new city or stronghold can be created but naturally it could create tensions being so close to Orgrimmar. Even if Jaina and Baine has a pow wow.
The Maghar Orc’s once learning that Blackrock Mountain is where the Horde was defeated and Turalyon slain Doomhammer. Could cause them to explore at first then begin to make incursions which would lead to confrontation with Dark Iron Dwarves. To keep themselves strong enough should they some day face Yrel in alternate Draenor or on Azeroth.
A full scale BFA sized war might not be what Blizzard are going for. But there can be smaller conflicts, racial tensions and wars instead of full blown faction warfare.
With Teldrassil gone there is no Night Elf presence to fight against Horde deforestation. Horde Druids did not seem to oppose this.
With the helm of domination destroyed (yes what it has become means it is gone forever including it’s legacy) There is not much or anything to keep the scourge in check, Their will had to be subjugated to the Lich King in order to keep them in check. So can see the Lightforged Draenai not landing in Northrend but securing a foothold, trying to bottleneck the scourge. They fought a war of attrition against the Legion so may be equipped to do so against the scourge.
However the Knights of the Ebon Blade seeing this as an incursion of the Light might work to become their own faction, Seperate to the living and the non-Forsaken Undead. Without the helm of domination they have to be strong enough to dominate the scourge.
The Darkspear does not have a home. While they honor the loa they are not really as religious as the Zandalari. So could be one of the voices that are connected to nature (Shaman and Druids) that could perhaps curtail aggressive Horde deforestation and expansion.
Remnants of the blood trolls might want the means of sacrificing loa from the Drakkari so this could cause the Darkspear to put a stop to it but end up getting caught in a long term campaign they were not prepared for.
Member berries are one thing. But moving the world and its inhabitants forward are another. New coastline ports villages and towns to show more of the navy’s of Kul Tiran’s and Zandalari sea faring race.
The Light and Shadow are always at odds this could be explored with arguments, butting heads and even difficulty to work with each other, Turalyon and Alleria being a couple will not change that. The Horde under Garrosh showed there was disagreements and tensions with other races despite being part of the same faction.
Hellscream calling Sylvannas a B-word before it was censored and the attempt to kill Vol’jin.
So with the Nightborne expanding their telemancy studies and establishing a network for the Horde. The Void Elfs could show some contribution outside of meat for the Alliance war machines. So explore void base transportation. Naturally working with Shadow Priests to shield others from the whispers of the void. Also in game quirks such as Paladin or Lightforged being unable to use them and a convenient mage portal.
Less head cannon and more realistic possibilities and motivations of how the world itself feels more real. Like Sillithus and Theramore there are very real changes. This could also redistribute player population, instead of most players being in the new area for gear, endless attempts at impossible loot drops of mounts tmog gear etc… It fills out other areas story and the world itself.