Warhammer - High Fantasy?
Yeah, you kinda lost me there matey.
Warhammer has always been high fantasy. Winds of magic, warpstone moon, dragons, demons, lizardmen, undead, interdimensional portals. The Empire is the 'lowest' fantasy faction in it, and even then there are Wizard schools, griffons, and priests channeling the power of a mythical demigod.
Of course, compared to the high fantasy of Warhammer, AoS has left the atmosphere completely, both figuratively and in fluff.