Let me tell you a little story. Years ago, before I purchased T, I would take her around the barrel pattern for a change of pace. She did it, at whatever gait I asked for.
Months later, a friend let me take her barrel racing horse around the pattern. Well let me tell you it was like riding a rocket! It was than that I realized that T did as I asked her, but her heart was not in it. My friends horses heart and soul was in barrel racing and I felt it.
Maybe your horse just isn't cut out to be a barrel racing horse. Maybe it's talents lay elsewhere, nothing wrong with that.
Good luck to you both.