I recently played WoW Classic in August of this year getting a character up to I believe lvl 30+ (I remember equipping gear from Scarlet Monastery). When I logged into Hearthstone recently I expected to have the Lady Liadrin Hero portrait since I got a new character past level 20. I’m just hoping to get it soon.
Maybe it has to be normal wow, not classic? That’s the only thing I can think of.
Just found from another forum someone confirmed that really sucks 
now I’m gonna need to buy another month of subscription just to get it
Normal WoW is free for the first 20 levels. No need to buy anything.