Um - he already beat Maidana. I agree the weak chin has hurt him but you can train to protect it. Steward was able to train Wlad and Lewis to protect their chins and they both ended up with good careers.
He did look good. He shut Collazo down & didn't allow for himself to get caught against the ropes or walk into anything. His level of ring control has improved greatly. Guerrero would have been a better test though..styles make fights.