But then all aliens should be attracted to human females too
Since the only prominent differences between the two is the skin color and the "hair tentacles", pretty much everything else is the same. Yet Asari are attractive to the whole galaxy and human females are not.
Nope.
Asari can have mind sex while also having physical sex (banshees show that asari are analogously equipped to human females, just upside down), and can stimulate the limbic system of every other alien in the ME spectrum, and are evolutionarily compelled to seek out new and different snu snu to encourage trait proliferation.
Human women don't have any of that.
Also krogan comments about lack of size and humps being "tiny".
Every species that returns is getting a visual upgrade both in variety and "verisimilitude", but if you expect asari to go from Star Control to Pitch Black in anatomy, you're going to be a sad panda.