He's going to make some appearance in the Argus Boss Fight and participate; and I'm sure that's all we'll be seeing of the most infamous villain of WoW.
I doubt we will be seeing Sargeras in WoW after that;There is no Sargeras without legion unless Legion makes a return, which I think developer will wanna avoid for a while.
If this becomes the case,
what a shitty waste and failed potential for Sargeras. Deathwing 2.0