With the end of BFA, came the end of all out war between the factions.
Thorough Shadowlands we cast out faction affiliation away for covenants, all the races fought a common yet terribly implemented foe.
In Dragonflight we will set out as explorers and support the flights. The conflict has passed and data mined npc's show that the divide between factions is healing slowly.
While many want to see the Alliance positioned as the bad guy of an expansion for once. It would just be a rehash of the Horde civil war during Garrosh's era.
In the end the faction divide seems only to serve PvP.
I admit that having an Orc or Forsaken walk through Stormwind safely would be unlikely, as would a Human or Night elf walking through the Undercity.
However the factions let Death Knights, Warlocks and all other kind of shady individuals wander around the capitals as long as they are considered "Heroes" (Our player characters).
We even have situations like the Dwarfs. Ironforge has the Dark Iron walking thought the city once more.
My solution - Allow player characters to join any faction. As champions (or whatever) the prestige should overrule old grievances.
To make PvP situations work in the story line. Borrow from the idea of FFXIV Free Company's. Merc forces that fight over points of interest works better than trying to explain why the Horde and Alliance still fight in many of the battlegrounds.
Preferably Dragonflight will continue to mend the divide between factions and allow for a new era.
Another Faction conflict would just be more of the same.