Board Thread:Questions and Answers/@comment-10797017-20130627100621/@comment-11477779-20130717045602

Maybe Ichigo got all the goods being as he's first-born. Karin was always sensitive to spirits but really started to be able to see them after Ichigo became a substitute Soul Reaper. Since all the awakenings during this time have been attributed to the Hôgyoku, Maybe only Karin had the potential to be more sensitive to spiritual beings and Yuzu didn't which is why only Karin's powers have increased. It looked like Karin might become more important to the storyline during the Fullbringer arc but so far nothing much. Don't know if that was a red herring or she'll become more important in the future? Maybe she is one of the five war potentials!