No, I really could care less on what my baby looked like. I think our appearance shapes many aspects of our personality, and I wouldn't want our child knowing we had wanted them to look a certain way.
I have to admit, it would be nice to know that our child is somewhat intelligent, but if the child was biologically related to my husband and I, the child would have a good chance of being quite smart. Our children will not be biologically related to us though, since we have chosen to adopt our children, and I'm one hundred percent okay with whoever they are regardless of color, appearance, height, etc.
No, do not spoil the surprise that mother nature has in store for you. If there is a potentially harmful medical condition involved, then all bets are off. It strikes me that people who want designer babies are not ready to be parents. Love them as they are they will love you back, but if they detect any resentment they will hold back.