He may be a perfect fit for the Edgedancers, but, as I see it, the Nahel Bond occurs in people who needs improvement. Kaladin has depression, Shalan has PTSD and split personality disorder (ish), Dalinar is alcoholic and also has PTSD, Renarin has his blood disease and autism, Jasnah had that traumatic experience when she was younger (and that I hope to know more about in this book). Even that Iriali shoemaker had regrets about his past as a petty thief and the murder. Adolin, however, is kind of perfect in his own way. He may be dumb as a rock and a little frivolous, but he accepts himself that way. Even after killing Sadeas, his primary concern was that his father wouldn't aprove, not that it was wrong. And, if I'm not mistaken, Brandon said that you need to have a crack in your soul to form a Nahel Bond.