I guess it could've been the stint at the covern in England, or that she didn't care too much what Kennedy thought of her. It was Kennedy that did all the running, there never seemed to be much of an attraction from Willow's side.

Then the series did tend to be a little young with all the relationships, perhaps because the characters were supposed to be very young. So a little immaturity would be expected. They did age from 15-22 from start to finish, so they would have to do a lot of growing up during that time.

*goes off before saying anything about season 8*