Asari probably look closer to banshees (only not as tall and bloaty), it's only our human brains that see them as human looking women.
Easily debunked...
Film exists in the Mass Effect universe. If the Asari were capable of doing some sort of indoctrination to make other people see them in a different form, it would only work with people that had actually met Asari. That isn't the case for about 90% of humanity, which still lives on Earth. They'd be seeing the true form of the Asari on the nightly news or in movies. In LotSB Shepard can also see Asari he or she has never met in the Shadow Broker's video archives, and they don't look different from other Asari. The stone carvings of primitive Asari in the temple of Athame on Illium also show them in their familiar forms. The same is also true for the sign for the Chora's Den, which is in the shape of an Asari.
If the Asari were doing some sort of mental shape-shifting it would also make it impossible for any doctor that isn't an Asari to treat an Asari patient, but from Huerta Memorial we know that isn't the case.
The dialogue with the bachelor party on Illium isn't supposed to be taken as a word-for-word canon discussion on Asari biology.