I believe he's still, lore-wise, a shaman but his ability to be one is being downplayed in the same way his positioning in the story has been downplayed since Legion in order to focus on other major characters.
I kind of liked the story that was emerging at that time with Thrall coming in crisis with himself and the elements. If it ends up all happening off screen, this journey of "self re-discovery" and what not, that would be a shame.
Knowing Blizzard, when the time comes for Thrall to return to the spotlight, he will just be clangin' n' bangin' lightning bolts and lava like nothing ever happened to him.