Dragons, griffins and fireballs compared to... high heels? Wat.
High heels are not unrealistic (and no one said that) but the context is very important. Don't know you but wearing high heels and open dresses during the Battle of KH is pure nonsense to me. Yen in Kaer Trolde during the feast? That's fine wearing high heels and dresses there, but not when you have to fight for your life.
Just an example, when Yen saved Dandelion's life in the books she was wearing a male outfit. (Sapkowski ftw)
Still, why those heels are so important? This game is full of nonsense anyways, if you want to put it like that. In real life you can't swim across the ocean with full armor and swords on, you can't fight like a maniac without your towel dropping off, you can't drink healing potions during a sword fight, why doesn't their hair get flat when it rains etc.
While watching this, remember that Ciri is Kaer Morhen trained "I'm a woman, I love wearing heels" (borrowed from video)
As I see it, Ciri loves heels and because she is Kaer Morhen trained, that's not a problem for her. How much simpler can it be?