The Gadol HaDor Rav Elyashiv zt’l” spoke very harshly against today’s sheitels.
These are the words of the Rav translated into English (there is a recording of this speech):
“Even though there’s a dispute among the Poskim whether it’s mutar or ossur to wear a sheitel, if they walk as if their hair is revealed, the way those that are not covering their hair walk, they are violating an issur gamur, it’s mamish, it’s emes like ervah. (the term used in gemara to describe parts of the body that must be covered according to halacha) The issur is as follows: If they walk with a sheitel like the times 100 years ago, then of course this is allowed, even a drop nicer. But, it should not be the way they walk today. All those that walk today, it looks like hair for sure and this is definitely assur, this nobody was mattir.…A woman with the hair of today the way she walks, it’s mamish ervah, it looks like hair, there is no difference, regarding this there is
no heter…”
A woman’s hair becomes ervah after marriage, and just like any other body part that is considered ervah, it must be covered and concealed. Wearing someone else’s “ervah” to cover one’s own ervah is making a mockery of this commandment. A wig today is an exact replica of the ervah that is being covered (usually nicer looking), it’s equivalent to a woman wearing a skintight dress with images on it of the body parts that are being covered.
Some interesting historical facts- the origin of this commandment really comes from Chava. After she sinned because of the snake, she hid her head in shame from doing this sin, and one of her punishments was hair covering (from the Maom Loez). The Torah source from the Sotah having her hair uncovered after she sinned was also an act of shame. The head covering is not meant to be a source of pride and vanity. It is solely meant to increase a married woman’s modesty level in front of other men, which none of the wigs accomplish today.