I mean story wise, just look at the recent
WoD was basically a plot device to bring Gul'dan back. Back from what exactly? You see MUCH of WoD was scrapped and rushed to Legion, and what happened then? They began resolving plotlines at a super fast pace.
In Legion, we destroy the burning legion, the number one threat, we wondered what happened to Illidan, and he got locked away at the phanteons seat, resolving his story. Alleria and Turalyon was also found, resolving their story aswell. There is also the stormheim attack which is the catalyst for the war. So the burning legion is gone. What does this mean?
No argus expansion. We could have had one but now it's HIGHLY unlikely.
After the attack, Sylvanas describes in a good war that she doesen't believe that Anduin can keep the piece, so she uses Teldrassil as a bargaining chip. So In battle for Azeroth we do 3 things. We resolve the faction conflict, we defeat Azshara, and we are likely to defeat N'zoth. What does that mean?
No more expansions like MoP/Bfa. The leadership of the horde has been replaced with one dimensional good characters.
Azshara is already defeated so this means no Naz'jatar/South Seas expansion
With N'zoth gone, this also means no Ny'alotha expansion.
So they basically, crammed 5 expansions into two story wise. So what do we have left? The only two explainations is... They are setting up to making a dickton of new lore, or they are prepared to move on.
I don't really think Yrel is worthy of her own expansion, and I think returning to Draenor is out of the equation
Some might say that Sargeras is stored off for later, but lets be honest, it aint gonna be an expansion, if anything he's going to ship up in the nick of time with illidan on his shoulders to kick the void lords asses.
Then we have the Lich king and/or the shadowlands
And then ???
Adventure expansions have always been about fighting for the resources, so unless blizzard is planning on doing another PvP expansion I dunno what else they could do