I beg to differ with the OP's complaint. As I and several other of my male friends with female characters were discussing one day while we were hanging out in our bikinis-- My seeker of the moon miqo'te clearly has the largest "equipment" among the three or four of us. Both of my Keeper of the Sun friends were small chested by comparison and the only one of us who came close was a female hyur.

I'd like to note that while making your character the different faces you choose makes a very prominent difference in your breast size (as was lol'd about upon the character creation teaser) so maybe you just got unlucky?