Togekiss, which turned out to be a completely pointless capture done so in such a terrible way that it still bothers me. I think that if Dawn had better and/or more interesting rivals, she could have had more personal development. Outside of her losing streak arc, it felt like most of her journey didn't affect her on a personal level, but rather just make her more determined to train and achieve her goal. She's still is a pretty likable character, but I agree that personality-wise, she didn't change drastically by the end of the series. At most, she seemed to handle her defeats much better than she did during her losing streak, although at times it felt like she took them too well, but that's the most I think she changed on a personal level.