If you use Ring of Broken Promises (turns you into Erinys) you can also get both old animations & models of Blood Elf Female aswell. Some of the newer animations they've made in Legion gets reverted to old animations. Just like new vs old shield slam, animation just converts.
Exactly same scenario with Noggenfogger elixir and so on. I don't understand why blizzard doesn't just let us play with old models & animations instead of forcing us into using the new ones.